CN104904141B

CN104904141B - Coherent communication system, communication method, and transmission method

Info

Publication number: CN104904141B
Application number: CN201480004694.4A
Authority: CN
Inventors: 石原浩; 石原浩一; 沟口匡人; 村上友规; 片冈智由; 木坂由明; 中川匡夫; 山崎悦史; 冈本圣司; 堀越建吾; 富泽将人; 工藤理; 工藤理一
Original assignee: Nippon Telegraph and Telephone Corp
Current assignee: Nippon Telegraph and Telephone Corp
Priority date: 2013-01-15
Filing date: 2014-01-15
Publication date: 2017-05-17
Anticipated expiration: 2034-01-15
Also published as: US9621299B2; EP2930864A4; US20150341138A1; EP3176964B1; EP3176964A1; JPWO2014112516A1; JP5873575B2; EP2930864A1; WO2014112516A1; CN104904141A; EP2930864B1

Abstract

The present invention enables measurement of a wavelength dispersion amount by the use of training signal sequences. This transmission method has: a training signal sequence generation step, wherein multiple signal sequences having power concentrated in multiple frequency bands, the power of said multiple signal sequences being concentrated in different frequency bands from each other, are generated as training signal sequences; a training signal sequence selection step, wherein at least one training signal sequence is selected among the multiple training signal sequences generated in the training signal sequence generation step; a signal multiplexing step, wherein a signal sequence is generated by time-multiplexing the training signal sequence selected in the training signal sequence selection step with a transmission data sequence; and an electrical-optical conversion step, wherein the signal sequence generated in the signal multiplexing step is converted into an optical signal and transmitted.

Description

Coherent communication system, communication means and sending method

Technical field

The present invention relates to coherent communication system as follows, communication means and sending method：In optical communications, pass through Special frequency band signal is sent with dispensing device and receive the signal come the wavelength in detection fiber transmission path with reception device Dispersion measure, based on its value of calculation wavelength dispersion compensation is carried out, and thus, compensates the mistake of the sending signal caused due to wavelength dispersion Very.

The application is based on January 15th, 2013 to the Patent 2013-004780 of Japanese publication and July 2 in 2013 Day claims priority to the Patent 2013-138928 of Japanese publication, and by their content quotation in this.

Background technology

In the field of optic communication, the synchronous detection mode and Digital Signal Processing of efficiency of frequency employment will be by leaps and bounds improved Combined digital coherent communication system is attracted attention.Known digital coherent communication system with built using direct detection be When system compares, receiving sensitivity can not only be improved, and can be by being received sending signal as digital signal To compensate the wave distortion of wavelength dispersion due to being subject to using fiber-optic transfer, the sending signal that polarized mode dispersion is caused, and And, discussing and imported as follow-on optical communication technique.

The digital coherent mode represented by non-patent literature 1 and non-patent literature 2 is adopted with the following method：With fixed numeral Wave filter（For example, for the signal of 28Gbaud, with the dispersion of 20000ps/nm, tap number is 2048tap）Compensation is quasi-static Wavelength dispersion and to have used blind arithmetic（blind algorithm）Little tap number（For example, with the polarization mould color of 50ps Dissipate, be 10 ~ 12tap or so）Sef-adapting filter compensation exist change polarized mode dispersion.

Prior art literature

Non-patent literature

Non-patent literature 1：H. Masuda, et. al.,“13.5-Tb/s（135x111-Gb/s/ch）No-Guard- Interval Coherent OFDM Transmission over 6,248 km using SNR Maximized Second- order DRA in the Extended L-band,” OSA/OFC/NFOEC 2009, PDPB5；

Non-patent literature 2：Jianjun Yu, et. al.,“17 Tb/s（161x114 Gb/s）PolMux-RZ-8PSK transmission over 662 km of ultra-low loss fiber using C-band EDFA amplification and digital coherent detection,”ECOC 2008, Th.3.E.2, Brussels, Belgium, in September, 2008 21-25 day.

The content of the invention

The invention problem to be solved

But, in the digital coherent mode of non-patent literature 1 and non-patent literature 2, need to determine wavelength in addition in advance Dispersion and to wavelength-division multiplex（WDM：Wavelength Division Multiplexing）Each receiver of channel with It is manually entered the tap coefficient of stationary digital wave filter.

The present invention considers such situation and completes, and its object is to offer one kind and has used optical signal in utilization Synchronous detection communication system in can carry out the estimation of wavelength dispersion amount using training sequence signal to compensate in light The coherent communication system of wavelength dispersion, communication means and the sending method being subject in fibre transmission.

For solving the scheme of problem

In order to solve the above problems, the present invention is a kind of coherent communication system, possesses optical signal transmitter and optical signal Reception device, wherein, the optical signal transmitter possesses：Training sequence signal generating unit, generate have concentrate on multiple frequencies Multiple signal sequences of the power of band, i.e. power concentrate on multiple signal sequences of each different frequency band as multiple training Signal sequence；Training sequence signal selector, from the plurality of training signal that the training sequence signal generating unit is generated At least one training sequence signal is selected in sequence；Signal multiplexing portion, generates the training sequence signal selector is selected The training sequence signal with send data sequence carry out it is time-multiplexed after signal sequence；And electrical/optical transformation component, will be described The signal sequence that signal multiplexing portion is generated is changed into optical signal to be transmitted, and the light signal receiving possesses：Light/ The converting optical signals sent from the optical signal transmitter are the signal of telecommunication by electric transformation component；Analog/digital conversion portion, It is digital signal sequences by the converting electrical signal after being converted by the optical electrical transformation component；Multiple frequency bandpass filter portions, It is corresponding respectively with the plurality of signal sequence, make the frequency of the digital signal sequences that the analog/digital conversion portion converted A part with component passes through；And multiple power calculation portions, respectively correspondingly set with the plurality of frequency bandpass filter portion Put, calculate the performance number of the digital signal sequences of corresponding frequency bandpass filter portion output.

Preferably, in above-mentioned coherent communication system, the training sequence signal generating unit generates power and concentrates on ratio The optical signal transmitter or the light signal receiving or the cut-off frequency in the band limiting filter in propagation path , used as the training sequence signal, the training sequence signal selector is based on described at least one signal sequence of little frequency Optical signal transmitter or the presence or absence of the light signal receiving or the band limiting filter in the propagation path, from At least one training sequence signal is selected in the plurality of training sequence signal that the training sequence signal generating unit is generated.

Preferably, in above-mentioned coherent communication system, the training sequence signal selector is sent out based on the optical signal Send stricturization, the transmission letter of the propagation path in frequency characteristic, the propagation path of device or the light signal receiving At least one among the estimated accuracy of the frequency characteristic in road, wavelength dispersion amount, transmission range and the wavelength dispersion amount, from At least one training sequence signal is selected in the plurality of training sequence signal that the training sequence signal generating unit is generated.

Preferably, in above-mentioned coherent communication system, the training sequence signal generating unit generates the frequency that power is concentrated The interval of the rate signal sequence bigger than predetermined interval is used as the training sequence signal.

Preferably, in above-mentioned coherent communication system, the training sequence signal selector selects multiple training signals Sequence, the signal multiplexing portion generates signal according to selected each training sequence signal of the training sequence signal selector Sequence, the electrical/optical transformation component sends multiple signal sequences that the signal multiplexing portion is generated in different planes of polarization.

Preferably, in above-mentioned coherent communication system, the signal multiplexing portion is being carried out with the transmission data sequence The surrounding time of time-multiplexed training sequence signal is multiplexed other training sequence signals.

Preferably, in above-mentioned coherent communication system, the light signal receiving is also equipped with：Training signal switches Portion, the maximum performance number in the performance number that the selection power calculation portion is calculated；And training sequence signal test section, base In the selected maximum performance number of the training signal switching part, concentrate on from digital signal sequences detection power The training letter of the frequency band that corresponding frequency bandpass filter portion of the power calculation portion of the performance number maximum with this is calculated is passed through Number sequence.

Preferably, in above-mentioned coherent communication system, the light signal receiving and the optical signal transmitter The information of the selected training sequence signal is had in advance, and the training signal switching part is only selected simultaneously using described information Export the input from frequency bandpass filter portion corresponding with the selected training sequence signal.

Preferably, in above-mentioned coherent communication system, the light signal receiving is based on the training sequence signal The positional information of the training sequence signal that test section is detected, selects and extracts comprising one from the digital signal sequences The interval of the part training sequence signal for detecting, the interval comprising the training sequence signal detected described in whole, with And any one interval not comprising the training sequence signal for detecting.

Preferably, in above-mentioned coherent communication system, the light signal receiving is also equipped with side-play amount calculating part, institute State institute of the side-play amount calculating part in the training sequence signal detected comprising a part of training sequence signal test section In stating interval or the interval comprising the training sequence signal that all the training sequence signal test section is detected Digital signal sequences in frequency shift (FS) is calculated based on the training signal switching part, the frequency bandpass filter portion is in base The digital signal sequences are compensated after the frequency shift (FS) in the frequency shift (FS) that the side-play amount calculating part is calculated, makes this The band component that the power of the training sequence signal in the frequency component included in digital signal sequences is concentrated passes through, institute State light signal receiving to be also equipped with：Multiple power calculation portions, respectively correspondingly set with the plurality of frequency bandpass filter portion Put, calculate the performance number of the digital signal sequences of corresponding frequency bandpass filter portion output；And transmission path information is calculated Portion, the performance number calculated based on the plurality of power calculation portion is calculating wavelength dispersion amount.

Preferably, in above-mentioned coherent communication system, the light signal receiving is also equipped with side-play amount calculating part, institute State institute of the side-play amount calculating part in the training sequence signal detected comprising a part of training sequence signal test section In stating interval or the interval comprising the training sequence signal that all the training sequence signal test section is detected Digital signal sequences in frequency shift (FS), the plurality of frequency bandpass filter portion are calculated based on the training signal switching part The frequency shift (FS) is compensated to the digital signal sequences in the frequency shift (FS) calculated based on the side-play amount calculating part Afterwards, the frequency band concentrated except the power of the training sequence signal in the frequency component included in the digital signal sequences is made Band component beyond component passes through, and the light signal receiving is also equipped with transmission path information calculating part, the transmission road The performance number that footpath information calculating part is calculated based on the plurality of power calculation portion is calculating noise power.

Preferably, in above-mentioned coherent communication system, the light signal receiving is also equipped with transmission path information meter Calculation portion, the transmission path information calculating part is in the training signal detected not comprising the training sequence signal test section Signal power is calculated in digital signal sequences in the interval of sequence.

Preferably, in above-mentioned coherent communication system, the frequency bandpass filter portion and the power calculation portion At least one is operated with the work clock slower than the work clock of the training sequence signal test section.

Preferably, in above-mentioned coherent communication system, the transmission path information calculating part is with than the training signal The work clock that the work clock in Sequence Detection portion is slow is operated.

Preferably, in above-mentioned coherent communication system, the side-play amount calculating part is with than training sequence signal inspection The work clock that the work clock in survey portion is slow is operated.

Preferably, in above-mentioned coherent communication system, share in the plurality of frequency bandpass filter portion into being about to The operational part of the FFT computings when digital signal sequences are transformed to the signal of frequency domain enters to be about to the digital signal sequence of frequency domain Arrange the operational part of IFFT computings when being inversely transformed into the signal of time domain.

Preferably, in above-mentioned coherent communication system, the transmission path information calculating part is according to ascending order or descending weight The estimated value of new arrangement multiple wavelength dispersion amounts obtained from by repeatedly determining, removes the Arbitrary Digit comprising maximum estimated value The upper estimated value of amount and any number of the next estimated value comprising minimum estimated value.

Preferably, in above-mentioned coherent communication system, the light signal receiving is also equipped with：Wavelength dispersion compensation Portion, the wavelength dispersion amount calculated based on the transmission path information calculating part is compensating by the digital signal sequences The distortion that causes of wavelength dispersion；Adaptive equalization portion, to by the digital signal sequences after wavelength dispersion compensation portion compensation Carry out equilibrium；And demodulation section, to being demodulated by the digital signal sequences after adaptive equalization portion equilibrium.

Additionally, the present invention is a kind of communication means, the communication means is the communication means in coherent communication system, its In, have：Training sequence signal generation step, generates multiple signal sequences, the i.e. work(with the power for concentrating on multiple frequency bands Rate concentrates on multiple signal sequences of each different frequency band as multiple training sequence signals；Training sequence signal selects step Suddenly, at least one instruction is selected from the plurality of training sequence signal generated in the training sequence signal generation step Practice signal sequence；Signal multiplexing step, generating will select the training letter selected in step in the training sequence signal Number sequence with send data sequence carry out it is time-multiplexed after signal sequence；Electrical/optical shift step, will walk in the signal multiplexing The signal sequence generated in rapid is changed into optical signal to be transmitted；Optical electrical shift step, will convert in the electrical/optical The converting optical signals sent in step are the signal of telecommunication；Analog/digital conversion step, will be in the optical electrical shift step The converting electrical signal after middle conversion is digital signal sequences；Frequency band pass filtering step, according to the plurality of signal sequence Each make in the analog/digital conversion step digital signal sequences after conversion band component a part Pass through；And power calculation step, calculate the power of each digital signal sequences obtained in the frequency band pass filtering step Value.

Additionally, the present invention is a kind of sending method, described sender method is the sending method in coherent communication system, its In, have：Training sequence signal generation step, generates multiple signal sequences, the i.e. work(with the power for concentrating on multiple frequency bands Rate concentrates on multiple signal sequences of each different frequency band as multiple training sequence signals；Training sequence signal selects step Suddenly, at least one instruction is selected from the plurality of training sequence signal generated in the training sequence signal generation step Practice signal sequence；Signal multiplexing step, generating will select the training letter selected in step in the training sequence signal Number sequence with send data sequence carry out it is time-multiplexed after signal sequence；And electrical/optical shift step, will answer in the signal It is changed into optical signal to be transmitted with the signal sequence generated in step.

Invention effect

According to the present invention, optical signal transmitter multiple signal sequences of the generation with the power for concentrating on multiple frequency bands, I.e. respectively the multiple signal sequences with variform frequency spectrum, as training sequence signal, are selectively cut according to light transmission path Multiple training sequence signals of the generation are changed, to comprising the signal sequence after time-multiplexed selected training sequence signal Signal is transmitted.In light signal receiving, in acceptance division corresponding with selected training sequence signal, Neng Gougen Wavelength dispersion amount is carried out according to the arrival time difference in the frequency band that the power of the training sequence signal included in the signal is concentrated Estimation.By compensating the wavelength dispersion amount for calculating such that it is able to improve the docking collection of letters number precision for being decoded.

Description of the drawings

Fig. 1 is the block diagram of the configuration example of the optical signal transmitter for illustrating first embodiment of the invention.

Fig. 2 is to illustrate transmission when carrying out time-multiplexed to training signal in optical signal transmitter preferably The figure of the example of signal sequence.

Fig. 3 illustrate first special frequency band signal sequence is carried out in this embodiment it is time-multiplexed in the case of The figure of the example of the frequency spectrum of sending signal.

Fig. 4 illustrate second special frequency band signal sequence is carried out in this embodiment it is time-multiplexed in the case of The figure of the example of the frequency spectrum of sending signal.

Fig. 5 is to illustrate to carry out utilizing nyquist filter in this embodiment in sending side（Nyquist filter） Frequency band limit and first special frequency band signal sequence carried out it is time-multiplexed in the case of sending signal frequency spectrum The figure of example.

Fig. 6 is to illustrate to carry out being limited and right using the frequency band of nyquist filter in this embodiment in sending side Second special frequency band signal sequence carry out it is time-multiplexed in the case of sending signal frequency spectrum example figure.

Fig. 7 is the block diagram of the configuration example for illustrating the light signal receiving in the embodiment.

Fig. 8 is the block diagram of the configuration example for illustrating the wavelength dispersion amount calculating part 1007 in the embodiment.

Fig. 9 is the block diagram of the configuration example for illustrating the training sequence signal test section 1102 in the embodiment.

Figure 10 is the block diagram of the configuration example for illustrating the frequency offset computations portion 1103 in the embodiment.

Figure 11 is the block diagram of the configuration example for illustrating the retardation calculating part 1104 in the embodiment.

Figure 12 is the outline of the example of the band filter in the first frequency band filter portion for illustrate the embodiment Figure.

Figure 13 is the outline of the example of the band filter in the second frequency band filter portion for illustrate the embodiment Figure.

Figure 14 is to illustrate the first averaging filter portion 1205-1 and the second averaging filter portion in the embodiment The figure of the output result of 1205-2.

Figure 15 is to illustrate to use the wavelength dispersion amount in the case of FFT and IFFT to calculate to be filtered in a frequency domain The block diagram of the configuration example in portion 1007.

Figure 16 is to illustrate the frequency offset computations portion used to be filtered in a frequency domain in the case of FFT and IFFT The block diagram of 1103 configuration example.

Figure 17 is to illustrate the retardation calculating part used to be filtered in a frequency domain in the case of FFT and IFFT The block diagram of 1104 configuration example.

Figure 18 is the block diagram of the configuration example for illustrating the wavelength dispersion amount calculating part 1007 for possessing time-domain window portion.

Figure 19 is to illustrate using FFT and IFFT and possess the wavelength in time-domain window portion to be filtered in a frequency domain The block diagram of the configuration example of dispersion measure calculating part 1007.

Figure 20 is to illustrate block diagrams of the SN in the embodiment than the configuration example of computing device 4.

Figure 21 is the figure of the summary of the interval decision for illustrating the calculating for being used for noise power in this embodiment.

Figure 22 is the block diagram for illustrating the configuration example of SN in the embodiment than computing device 4B.

Figure 23 is the figure of the frequency spectrum for illustrating the special frequency band signal sequence after the transmission for determining in an experiment.

Figure 24 is the figure of the structure for illustrating Mach-Zehnder type photomodulators.

Figure 25 is to illustrate that the frequency spectrum for sending data sequence and the frequency spectrum of special frequency band signal sequence are the specific of proportionate relationship The figure of the example of band signal sequence.

Figure 26 is the density and transmission data sequence at the interval for illustrating the frequency that the power of special frequency band signal sequence is concentrated Power level have proportionate relationship special frequency band signal sequence frequency spectrum an example figure.

Figure 27 is to illustrate power level and the coherent communication system at each frequency that the power of special frequency band signal sequence is concentrated The proportion of goods damageds of the frequency characteristic in system are the figure of an example of the frequency spectrum of the special frequency band signal sequence of inversely prroportional relationship.

Figure 28 is the block diagram of the configuration example for illustrating the optical signal transmitter in second embodiment of the invention.

Figure 29 is the skeleton diagram for illustrating the sending signal frame format in the embodiment.

Figure 30 is the block diagram of the configuration example for illustrating the light signal receiving in the embodiment.

Figure 31 is to illustrate the utilization computer simulation when first special frequency band signal is used as into training sequence signal The figure of the result of calculation of wavelength dispersion value.

Figure 32 is to illustrate the utilization computer simulation when second special frequency band signal is used as into training sequence signal The figure of the result of calculation of wavelength dispersion value.

Specific embodiment

Hereinafter, on one side referring to the drawings, while explaining embodiments of the present invention.In embodiments of the present invention Optical signal transmitter and light signal receiving are used for for example using the fiber-optic transfer of the synchronous detection for having used optical signal The coherent communication systems such as system.

（First embodiment）

First, the first embodiment of the present invention is illustrated.

Fig. 1 is the block diagram of the configuration example for illustrating the optical signal transmitter in first embodiment of the invention.In the figure, 101 is sending signal modulation portion, and 102 is signal multiplexing portion, and 103 is electrical/optical transformation component, 104-l（1≤l≤L, L are more than 2 Integer）It is training sequence signal generating unit, 105 is training sequence signal selector.Optical signal transmitter possesses sending signal Modulation portion 101, signal multiplexing portion 102, electrical/optical transformation component 103, L training sequence signal generating unit 104-1 ~ 104-L and Training sequence signal selector 105.

The binary sequence of the data of 101 pairs of transmissions of sending signal modulation portion is modulated, and output sends symbol sebolic addressing.Make For modulation system, such as BPSK can be enumerated（Binary Phase Shift Keying, binary phase shift keying）Modulation, QPSK （Quadrature Phase Shift Keying, QPSK）Modulation, QAM（Quadrature Amplitude Modulation, quadrature amplitude modulation）Deng however, it can be the modulation system beyond it.Training sequence signal generating unit 104-l（l = 1, 2, …, L）It is the special frequency band signal sequence for generating the power with the special frequency band for concentrating on more than 2 The block of row, generate in L block respectively different frequency spectrum shape special frequency band signal sequence as training sequence signal simultaneously Exported.

The L kind training sequence signals that training sequence signal selector 105 is input into from self-training signal sequence generating unit 104-l Middle selection at least one, selected training sequence signal is exported to signal multiplexing portion 102.Training sequence signal selector 105 Based on the stricturization in the frequency characteristic of optical signal transmitter or above-mentioned light signal receiving, propagation path, propagation path The frequency characteristic of transmission channel, wavelength dispersion amount, the estimated accuracy of transmission range and wavelength dispersion amount at least one To be selected from L kind training sequence signals at least one training sequence signal.Further, believing in optical signal transmitter or above-mentioned light Include in the frequency characteristic of number reception device：The frequency characteristic of the digital band limiting filter in each device, power amplifier, number Frequency characteristic in the leading sections such as word/analogue converter, analog-to-digital converter, analog band-pass filter, each frequency component Received signal power or received signal power to noise power ratio etc..

Signal multiplexing portion 102 is made by the output of sending signal modulation portion 101 and the output of training sequence signal selector 105 To be input into, to the transmission symbol sebolic addressing as the output signal from sending signal modulation portion 101 according to each arbitrary letter Number cycle Ns（Ns >=1, Ns is more than 1 integer）Insertion（It is multiplexed in time）As from training sequence signal selector The training sequence signal of 105 output, exports as signal sequence obtained from its result.Electrical/optical transformation component 103 answers signal With the output in portion 102 as input, the electrical/optical conversion of signal sequence is carried out, export optical signal.Further, electrical/optical transformation component 103 Each signal sequence is exported in the case where signal multiplexing portion 102 exports multiple signal sequences in the different plane of polarization of optical signal.

Fig. 2 is the figure of an example of the sending signal sequence of the optical signal transmitter output for illustrating present embodiment. As shown in the drawing, will be by Nt according to each Ns symbol（Nt >=1, Nt is more than 1 integer）Symbol constitute training signal with Send data signal carry out it is time-multiplexed, thus, generate sending signal sequence.Further, training signal can also be discussed as ginseng Examine signal, pilot signal, known signal etc..

Here, as special frequency band signal sequence, for example, it is point-symmetric that can use in IQ planes relative to origin The alternating signal of relation.For example, bpsk signal can be generated and-S, S ,-S, S ... is alternately used ,-S, S this 2 Signaling point generates QPSK signals and uses（S, S）, （-S, -S）, （S, S）, （-S, -S）, …, （S, S）, （-S, -S）Or（S, -S）, （-S, S）, （S, -S）, （-S, S）, …, （S, -S）, （-S, S）Such signal Sequence.Here, S represents arbitrary real number.Additionally,（α, β）Real part, the component of signal of imaginary part are represented, as plural number, Neng Goubiao It is shown as α+j β.J is imaginary unit.

It is further possible to using such as-S ,-S, S, S ,-S ,-S, S, S ... ,-S ,-S, S, S are like that by 1 Individual signal repeats M time（M is arbitrary integer, in this M=2）Alternating signal afterwards.Additionally, by will be with multiple numbers of repetition pair The signal mixing answered or convolution such that it is able to generate the special frequency band signal that the frequency band more than 4 has peak value.Additionally, Different multiple sine waves and it is added by the generation cycle, so as to the band signal of the characteristic frequency that also can generate more than 2. Additionally, using OFDM（OFDM：Orthogonal Frequency Division Multiplexing）Mode, only In specific subcarrier sending signal, thus, it is also possible to generate the band signal of characteristic frequency.

Method with more than generates multiple special frequency band signal sequences, from wherein selecting 1, by itself and transmission data signal Carry out time-multiplexed.

Here, as an example, it is considered to following situation：In the sending signal transmission of 30Gbaud, there are 2 training Signal sequence generating unit 104-1,104-2（L=2）, QPSK signals are generated by training sequence signal generating unit 104-1（S, S） With（-S, -S）Such alternating signal as first special frequency band signal sequence, by training sequence signal generating unit 104-2 Generate such as（S, S）, （S, S）, （-S, -S）, （-S, -S）, （S, S）, …, （S, S）, （S, S）, （-S, - S）, （-S, -S）The signal sequence of the QPSK signals after so 1 signal is repeated 2 times is used as second special frequency band signal Sequence.

Fig. 3 is to illustrate first special frequency band generated to training sequence signal generating unit 104-1 in present embodiment Signal sequence carry out it is time-multiplexed in the case of sending signal frequency spectrum figure.Additionally, Fig. 4 is illustrated in present embodiment To training sequence signal generating unit 104-2 generate second special frequency band signal sequence carry out it is time-multiplexed in the case of send out The figure of the frequency spectrum of the number of delivering letters.In figs. 3 and 4, transverse axis represents frequency, and the longitudinal axis represents the power at frequency component（Power）.Again Have, the signal for being shown with negative in a frequency domain is the component of turning back of the signal corresponding with 30GHz ~ 60GHz in the signal of telecommunication, but Be, when be up-converted for optical signal when, be converted to negative region compared with carrier frequency, therefore, in figs. 3 and 4 as this Sample labelling.

In figure 3, it is able to confirm that：In the case of first special frequency band signal sequence, 15GHz high frequency side and- The lower frequency side of 15GHz is formed with 2 signals with 30GHz intervals.Additionally, in the diagram, it is able to confirm that：It is specific at second In the case of band signal sequence, 2 powerful frequency spectrums are formed with the high frequency side of 7.5GHz and the lower frequency side of -7.5GHz, 2 low power frequency spectrums are formed with the high frequency side of 22.5GHz and the lower frequency side of -22.5GHz, add up to 4 frequency spectrums.Namely Say, the power of the frequency spectrum of second special frequency band signal sequence concentrates on the work(of the frequency spectrum with first special frequency band signal sequence The different frequency band of frequency band that rate is concentrated.

By the way that special frequency band signal is used as into training sequence signal, so as to the little signal of the width for becoming each frequency spectrum itself Light, accordingly, it is difficult to be subjected to the waveform deterioration that wavelength dispersion is caused.Further, since mutual frequency spectrum is separated, so, when receiving When wavelength dispersion, arrival time difference is produced.Using the situation, wavelength can be calculated using the method as shown in following Dispersion measure.

Additionally, generating first special frequency band signal sequence and power concentrate on the frequency bands different from first frequency band the Two special frequency band signal sequences, select any one to carry out time-multiplexed and send by training sequence signal selector 105, by This, the stricturization of the signal in repeater that can be in transmission path（PBN：Path Band Narrowing, path frequency Band stricturization）, transceiver（Optical signal transmitter or light signal receiving）Power amplifier, digital-to-analog converter （DAC）, analog-to-digital converter（ADC）, analog band-pass filter（BPF：Band Pass Filter, band filter）Deng Front end（FE）The impact of the frequency characteristic or cut-off frequency in portion, the cut-off frequency of digital BPF of transceiver etc. is adaptively cutting Change special frequency band signal sequence, therefore, it is possible to carry out acceptance division in wavelength dispersion estimation.

Here, as a benchmark for being used as training signal is selected from multiple special frequency band signal sequences, can enumerate The signal in repeater in the shape of the digital band limiting filter of transceiver, cut-off frequency or frequency characteristic, transmission path Stricturization, filter shape or frequency characteristic, the frequency characteristic of the propagation channel of transmission path, the wavelength dispersion amount to be estimated or Its maximum, transmission range or its maximum, the power amplifier of transceiver, digital-to-analog converter, analog/digital conversion The reception letter of the frequency characteristic of the leading sections such as device, analog band-pass filter, filter shape or cut-off frequency, each frequency component Number power or received signal power to noise power ratio, the estimated accuracy of required wavelength dispersion amount at least one.

Specifically, the number tape limit filter for determining or predicting transceiver according to the advance signal for transmitting or the signal in transmission The stricturization of the signal in repeater in the shape of ripple device, cut-off frequency or frequency characteristic, transmission path, filter shape or Frequency characteristic, the frequency characteristic of the propagation channel of transmission path, the power amplifier of transceiver, digital-to-analog converter, mould The frequency characteristic of the leading sections such as plan/digitalizer, analog band-pass filter, filter shape or cut-off frequency, each frequency The received signal power or received signal power of component to noise power ratio etc., using training signal received signal power or connect Signal power is received to noise power ratio, the bit error rate of transmission signal or Q-value, the constellation of transmission symbol（constellation） Control information etc. selecting to obtain the training signal of superior characteristic.

As an example, to illustrate and use the nyquist filtering of roll-off rate α=0.1, cut-off frequency 15GHz in sending side Device is used as digital BPF and makes situation about passing through in digital BPF from the signal of telecommunication of the output of signal multiplexing portion 102.Fig. 5 is to show Go out sending side carry out using nyquist filter frequency band limit in the case of to first special frequency band signal sequence The figure of the frequency spectrum of sending signal when carrying out time-multiplexed.Additionally, Fig. 6 is to illustrate to carry out utilizing nyquist filtering in sending side The frequency spectrum of sending signal when carrying out time-multiplexed to second special frequency band signal sequence in the case of the frequency band restriction of device Figure.

It can be seen from Fig. 5 and Fig. 6, in the situation for applying to be limited using the frequency band of nyquist filter to sending signal Under, first special frequency band signal sequence precisely the presence of in the cut-off frequency identical position with nyquist filter, therefore, Power is changed into 1/4 times.On the other hand, second special frequency band signal sequence is in the inner side of the cut-off frequency of nyquist filter There are 2 frequency spectrums, therefore, also it is capable of detecting when training sequence signal after by nyquist filter.In described above In, as an example, the explanation of the digital BPF of sending side is carried out, but, the digital BPF's, transceiver for receiving side The leading sections such as power amplifier, digital-to-analog converter, analog-to-digital converter, analog band-pass filter, propagation path etc. In cut-off frequency be also that similarly, first special frequency band signal sequence is precisely the presence of in the cut-off with nyquist filter Frequency identical position, therefore, power is changed into 1/4 times.On the other hand, second special frequency band signal sequence is in Nyquist There are 2 frequency spectrums in the inner side of the cut-off frequency of wave filter, therefore, instruction is also capable of detecting when after by nyquist filter Practice signal sequence.

Additionally, there are following situation：According to the shape or frequency characteristic, transmission path of the digital band limiting filter of transceiver In repeater in signal filter shape or frequency characteristic, the frequency characteristic of the propagation channel of transmission path, transceiver The leading section such as power amplifier, digital-to-analog converter, analog-to-digital converter, analog band-pass filter frequency characteristic Or filter shape etc., in the frequency band more than certain frequency, it was observed that group delay or the decay of power, it is impossible to obtain sufficiently Estimated accuracy.In this case, converged on below said frequencies by being set as 2 frequency spectrums of special frequency band signal sequence, from And wavelength dispersion can be estimated.

Additionally, according to wavelength dispersion amount or its maximum, transmission range or its maximum to be estimated, the spy for illustrating afterwards Determine the arrival time difference of 2 frequency spectrums in receiving side of band signal sequence（Delay-time difference）Change, thus, it is also possible to according to will The wavelength dispersion amount or its transmission range of estimation is selecting training signal.Specifically, as shown by afterwards, wavelength dispersion Amount or its transmission range become bigger, in the arrival time difference of receiving side（Delay-time difference）Become bigger, accordingly, there exist in electricity The situation of the higher limit of the time delay difference that can be estimated is determined in the design of road.Therefore, now, select to converge in the range of this As special frequency band signal sequence be used as training sequence signal.Even that is, identical wavelength dispersion amount or Its transmission range, more arrowband, arrival time difference（Delay-time difference）Become less, therefore, as long as selecting to converge on above-mentioned Special frequency band signal sequence as limit value is used as training sequence signal.Thereby, it is possible in the change for not carrying out circuit The estimation of wavelength dispersion is carried out in the case of more.

Further, it is contemplated that following situation：According to the shape or frequency characteristic, transmission path of the digital band limiting filter of transceiver In repeater in signal filter shape or frequency characteristic, the frequency characteristic of the propagation channel of transmission path, transceiver The leading section such as power amplifier, digital-to-analog converter, analog-to-digital converter, analog band-pass filter frequency characteristic Or filter shape etc., the received signal power or received signal power of each frequency component is different to noise power ratio.At this In the case of, the received signal power or received signal power of each frequency component are surveyed to noise power ratio in receiving side Fixed etc., selection is believed special frequency band as noise power ratio highest in receiving side received signal power or received signal power Number sequence is used as training signal and also may be used.Thereby, it is possible to improve received signal power or received signal power to noise power ratio, The estimated accuracy of wavelength dispersion is improved.

Here, it is preferable that, by the first special frequency band signal sequence generated by training sequence signal generating unit 104-1 Power concentrate frequency band and by training sequence signal generating unit 104-2 generate the second special frequency band signal sequence in power The frequency setting interval of the frequency band of concentration must be than the frequency that can produce between light signal receiving and optical signal transmitter Rate offsets（For example, the frequency departure of the laser used in light signal receiving and optical signal transmitter）Maximum Greatly.It is bigger than the maximum of the advance frequency shift (FS) envisioned by the way that the interval of frequency is set to such that it is able to easy in receiving side Ground the first special frequency band signal sequence of identification and the second special frequency band signal sequence.

Additionally, generate at least one than due to transmission path, the FE portions of transceiver, the digital BPF of transceiver and produce big There is the training sequence signal as special frequency band signal at the less frequency of the frequency band of the decay of power, thus, all Situation under can receiver side detect training sequence signal, wavelength dispersion can be estimated.

Like this by multiple training sequence signal generating units 104-l（l=1, 2, …, L）What is generated respectively is multiple specific Band signal sequence is imported in training sequence signal selector 105.Training sequence signal selector 105 is from multiple specific frequencies One is selected among band signal sequence, selected special frequency band signal sequence is input in signal multiplexing portion 102.Signal is answered The special frequency band signal sequence being input into is multiplexed in the time domain the transmission being input into from sending signal modulation portion 101 with portion 102 Ad-hoc location among signal.After being multiplexed to sending signal and special frequency band signal sequence in signal multiplexing portion 102 Signal is transmitted by electrical/optical transformation component 103 as optical signal.Now, in different plane of polarization parallel transmission training signal sequences Row, thereby, it is possible to obtain diversity gain, to polarization dependence loss robust are become（robust）.

Fig. 7 is the block diagram of the configuration example for illustrating the light signal receiving in present embodiment.In the figure, 1001 is pole It is optical electrical transformation component to change cutting part, 1002-1 and 1002-2, and 1003-1 and 1003-2 is analog/digital conversion portion, 1004-1 and 1004-2 is wavelength dispersion compensation portion, and 1005 is adaptive equalization portion, and 1006 is demodulation section, and 1007 is that wavelength dispersion amount is calculated Portion.Light signal receiving in present embodiment possess polarization division portion 1001, optical electrical transformation component 1002-1 and 1002-2, Analog/digital conversion portion 1003-1 and 1003-2, wavelength dispersion compensation portion 1004-1 and 1004-2, adaptive equalization portion 1005, Demodulation section 1006 and wavelength dispersion amount calculating part 1007.

1001 pairs, the polarization division portion optical signal for being received carries out in the optical domain polarization division, and the light after polarization division is believed Number export to optical electrical transformation component 1002-1 and optical electrical transformation component 1002-2.Polarization division portion 1001 for example possesses polarity diversity 90 Degree hybrid coupler（hybrid coupler）With local oscillations light source, thereby, it is possible to the optical signal for being received is divided into into two Individual orthogonal polarized wave.Here, in order that a polarized wave in two orthogonal polarized waves simply, is referred to as X polarization by explanation Ripple, by another polarized wave Y polarized waves are referred to as.Polarization division portion 1001 exports X polarization wave direction optical electrical transformation component 1002-1, By Y polarization wave direction optical electrical transformation component 1002-2 outputs.

Optical electrical transformation component 1002-i（i=1、2）By the X polarized waves of the optical signal for transmitting in a fiber and being received or Y poles Change ripple as input, X polarized waves or Y polarized waves are transformed to into the signal of telecommunication, its result is defeated to analog/digital conversion portion 1003-i Go out.Specifically, optical electrical transformation component 1002-1 and optical electrical transformation component 1002-2 uses local oscillator light by the photoelectricity of the flashlight being input into Field is separated into orthogonal component, and the component after separation is transformed to into electric analoging signal.Analog/digital conversion portion 1003-i（i=1、 2）/ digital conversion will be simulated as input from the signal of telecommunication of optical electrical transformation component 1002-i, will be converted（Sampling）For number Reception signal output after word.From analog/digital conversion portion 1003-i（i=1、2）The digital received signals of output are imported into ripple In long dispersion compensation portion 1004-i.

Wavelength dispersion compensation portion 1004-1 and wavelength dispersion compensation portion 1004-2 is using the reception signal of numeral as input, base The distortion of the signal caused due to wavelength dispersion is compensated in the wavelength dispersion amount calculated by wavelength dispersion amount calculating part 1007, And export its result.Wavelength dispersion amount calculating part 1007 is by wavelength dispersion compensation portion 1004-1 and wavelength dispersion compensation portion 1004-2 Output result as input calculating wavelength dispersion amount, using its result of calculation as output valve to wavelength dispersion compensation portion 1004-1 and wavelength dispersion compensation portion 1004-2 is exported.Adaptive equalization portion 1005 will be by wavelength dispersion compensation portion 1004-1 and ripple Digital received signals after long dispersion compensation portion 1004-2 compensation as input, to polarized mode dispersion and on transceiver, transmission road The signal of distortion is compensated in footpath, and result exported to demodulation section 1006.Demodulation section 1006 will be by adaptive equalization portion Digital received signals after 1005 compensation are demodulated as input, the docking collection of letters number, export demodulation result.

Here, wavelength dispersion compensation portion 1004-1 and wavelength dispersion compensation portion 1004-2 and the energy of adaptive equalization portion 1005 Enough frequency domain equalizations by illustrating in list of references 1 respectively（FDE：Frequency Domain Equalization）And when Domain is balanced（TDE：Time Domain Equalization）Method be operated.

（List of references 1）R. Kudo, T. Kobayashi, K. Ishihara, Y. Takatori, A. Sano, and Y. Miyamoto,“Coherent optical single carrier transmission using overlap frequency domain equalization for long-haul optical systems,”J. Lightwave Technology, vol. 27, no. 16, pp. 3721-3728,2009 Augusts.

Moreover, it is assumed that wavelength dispersion compensation portion 1004-1 and wavelength dispersion compensation portion 1004-2 is by wavelength dispersion amount 0ps/nm It is set as initial value, the wavelength dispersion amount calculated based on wavelength dispersion amount calculating part 1007 is updating the value.Additionally, in Fig. 7 In shown structure, the input of wavelength dispersion amount calculating part 1007 is the output of wavelength dispersion compensation portion 1004-1 and 1004-2, But it is also possible to using the output of analog/digital conversion portion 1003-1 and 1003-2 as input.In this case, wavelength dispersion Amount calculating part 1007 always being capable of mending in wavelength dispersion compensation portion 1004-1 and wavelength dispersion compensation portion 1004-2 is not subject to Estimate wavelength dispersion amount in the case of repaying the impact of error.

Fig. 8 is the block diagram of the configuration example for illustrating the wavelength dispersion amount calculating part 1007 in present embodiment.In the figure, 1101-1 and 1101-2 represent memorizer, and 1102 represent training sequence signal test section, and 1103 represent frequency offset computations portion, 1104 represent retardation calculating part.Wavelength dispersion amount calculating part 1007 has memorizer 1101-1 and 1101-2, training signal sequence Row test section 1102, frequency offset computations portion 1103 and retardation calculating part 1104.

From the X polarized waves of wavelength dispersion compensation portion 1004-i outputs or the signal sequence of Y polarized waves by as input signal It is input to memorizer 1101-i（i=1、2）In.Memorizer 1101-i based on training sequence signal test section 1102 output according to Each insertion cycle Ns of training is only delayed to interval and before and after it the interval signal sequence comprising training sequence signal Rush and export.With regard to the interval signal sequence beyond it, deleted.

Training sequence signal test section 1102 will be from wavelength dispersion compensation portion 1004-1 and wavelength dispersion compensation portion 1004-2 The X polarized waves of output and the signal sequence of Y polarized waves detect the on position of training sequence signal as input.Here, conduct The detection method of the on position of training sequence signal, for example, in the interval of the insertion cycle Ns of training sequence signal, calculates The frequency band that special frequency band signal sequence can be present（Have also contemplated that the frequency band of the impact caused due to frequency shift (FS)）Signal work( Rate, moment when detection signal power exceedes peak value or certain threshold value is used as the on position of training sequence signal, or, The training sequence signal for sending in advance is in the case of known to receiving side by obtaining the training signal and receiving the mutual of signal Close and detect the peak value of power to detect the on position of training sequence signal.

Additionally, training sequence signal test section 1102 is to memorizer 1101-1 and memorizer 1101-2 output control signals, So that based on the on position in the above-mentioned training sequence signal for detecting only buffers packet containing training sequence signal interval and Interval signal sequence before and after it.Additionally, training sequence signal test section 1102 by with judge special frequency band signal sequence The related information of species export to frequency offset computations portion 1103 and retardation calculating part 1104 as control information.

Frequency offset computations portion 1103 by from the output signal sequence of memorizer 1101-1 and memorizer 1101-2 and come The control information of self-training signal sequence test section 1102 calculates frequency shift (FS) as input.Frequency offset computations portion 1103 will The result of frequency offset computations to retardation calculating part 1104 is exported.Here, frequency shift (FS) is by calculating special frequency band signal The frequency offset of sequence is asking for.Additionally, frequency offset computations portion 1103 by with the special frequency band signal sequence for judging The related information of species is exported as control information to retardation calculating part 1104.

Retardation calculating part 1104 is by the output of memorizer 1101-1 and memorizer 1101-2, frequency offset computations portion 1103 Output and from training sequence signal test section 1102 control information as input, calculate special frequency band signal sequence The relative time of respective frequency spectrum is poor（Retardation）.

In the wavelength dispersion amount calculating part 1007 for constituting as shown in Figure 8, the detection instruction of training sequence signal test section 1102 Practice the on position of signal sequence, to memorizer 1101-1 and memorizer 1101-2 output control signals, so that only buffers packet contains The interval of the training sequence signal for being detected and the interval signal sequence before and after it.Therefore, the He of frequency offset computations portion 1103 Retardation calculating part 1104 is used only in the interval of the insertion cycle Ns of training sequence signal and is stored by the signal for buffering counting Calculate frequency offset and retardation.The insertion cycle Ns of training sequence signal is bigger relative to the signal sequence of buffering, then more energy Enough make process work and the training sequence signal test section 1102 of frequency offset computations portion 1103 and retardation calculating part 1104 Process work to compare and become low speed, by making synchronous circuit in work clock frequencies go lower, so as to realize low power consumption, Circuit scale is cut down.Further, as long as according to every U（U >=2, U is integer）Individual frame is estimating frequency offset and retardation In the case of, compared with according to situation about being estimated per 1 frame, work clock can be reduced, can realize further low Power consumption, circuit scale are cut down.

Additionally, as shown in Figure 18, in wavelength dispersion amount calculating part 1007, in memorizer 1101-i（i=1、2）'s Outlet side possesses time-domain window portion 1105-i（i=1、2）, thereby, it is possible to make to be input to frequency offset computations portion 1103 and retardation The S/N increases of the training sequence signal in calculating part 1104.Time-domain window portion 1105-i（i=1、2）Based on from training sequence signal The positional information of the training sequence signal of the output of test section 1102 is in some or all of mode comprising training sequence signal Less arbitrary signal sequence is extracted from the signal sequence of buffering and zero replacement is carried out to the part beyond it.Thus, energy Enough wave distortion, noise powers for reducing depending on signal mode.Or, in time-domain window portion 1105-i（i=1、2）In, it is based on From the positional information of the training sequence signal of the output of training sequence signal test section 1102, with the side not comprising training sequence signal Formula extracts signal sequence from the signal sequence of buffering, also, carries out zero replacement to the interval beyond it.Thereby, it is possible to extract The data signal sequence of training sequence signal is eliminated, therefore, it is possible to calculate the signal power for receiving signal.With regard to receiving signal Signal power, it is possible to use the power calculation portion being described below is being calculated, it is also possible to possesses and receives letter for calculating Number signal power special calculating part.Further, Figure 18 is that time-domain window portion 1105-i has been added to Fig. 8（i=1、2）Knot Structure, but it is also possible to add time-domain window portion 1105-i using to Figure 15 as shown in Figure 19（i=1、2）Structure.

Additionally, in the retardation calculating part 1104 shown in Fig. 8, it is also possible to enter row buffering to multiple estimated value, output The meansigma methodss of these estimated values.Further, it is also possible to rearrange the multiple estimated value of buffering according to ascending order or descending, removing After upper any number of estimated value comprising maximum and the next any number of estimated value comprising minima, Meansigma methodss are calculated, the meansigma methodss are exported as estimated value.Thus, even if due to depending on the waveform of signal mode to lose Very, instantaneous mistake and make estimated value output exception value, it is also possible to remove its impact.

Fig. 9 is the block diagram of the configuration example for illustrating the training sequence signal test section 1102 in present embodiment.In the figure, 2101-1-l（1≤l≤L, L >=2）And 2101-2-l（1≤l≤L, L >=2）Represent band filter portion, 2102-l（1≤l≤ L, L >=2）Signal power calculating part is represented, 2103 represent training signal switching part, and 2104 represent timing detection unit.Training signal Sequence Detection portion 1102 has 2 × L band filter portion 2101-1-1 ~ 2101-1-L, 2101-2-1 ~ 2101-2-L, L letter Number power calculation portion 2102-1 ~ 2102-L, training signal switching part 2103 and timing detection unit 2104.

Band filter portion 2101-1-l（1≤l≤L, L >=2）To from wavelength dispersion compensation portion 1004-1（Fig. 7）Output The sequence of X polarized waves enters to exercise the band filter that the component of predetermined frequency band passes through（BPF）Process.Band filter Portion 2101-2-l（1≤l≤L, L >=2）To from wavelength dispersion compensation portion 1004-2（Fig. 7）The sequence of the Y polarized waves of output is carried out Make the process of the band filter that the component of predetermined frequency band passes through.Here, training sequence signal test section 1102 is directed to X Polarized wave and Y polarized waves possess respectively the band filter portion 2101-1-l and band filter portion 2101-2- as L kinds BPF l.Each L kind BPF is the wave filter that the component of signal of the training sequence signal for making different passes through, complete with what is used in sender side The species of portion's training sequence signal is arranged in correspondence with.

Signal power calculating part 2102-l（1≤l≤L, L >=2）For from band filter portion 2101-1-l（1≤l≤L, L≥2）With band filter portion 2101-2-l（1≤l≤L, L >=2）The signal of change signal power of output.Training signal switches Portion 2103 is by L kind signal power calculating part 2102-l（1≤l≤L, L >=2）The signal power for calculating selects tool as input There is the sequence of the maximum signal power in the signal power calculated in each sequence and export to timing detection unit 2104. Additionally, training signal switching part 2103 is exported the information of the sequence of selection as control information.Timing detection unit 2104 The position of insertion training is judged according to the signal sequence exported from training signal switching part 2103, and using its result as control letter Breath output.

As an example, 2 specific frequencies as shown in the Fig. 3 and Fig. 4 used in by described above In the case that band signal sequence is transmitted as the sending signal of 30Gbaud, training sequence signal test section 1102 possesses band Bandpass filter portion 2101-1-1 and band filter portion 2101-2-1 and band filter portion 2101-1-2 and band filter Portion 2101-2-2 this L=2 kind band filter（BPF）.

In band filter portion 2101-1-1 and band filter portion 2101-2-1, use and make 15GHz and -15GHz Centered on frequency and respectively with ± △ f bandwidth BPF so that first special frequency band signal sequence passes through.In band logical In wave filter portion 2101-1-2 and band filter portion 2101-2-2, use using 7.5GHz and -7.5GHz as mid frequency simultaneously And respectively with ± △ f bandwidth BPF so that second special frequency band signal sequence passes through.

Here, as the setting value of △ f, it is preferred that the maximum frequency offseting value that setting is contemplated that（For example, most In the case that big frequency shift (FS) is 5GHz, △ f=5GHz）Or the specific frequency for not making beyond desired special frequency band signal sequence Band signal sequence is by such value（For example, in the case where above-mentioned 2 special frequency band signal sequences are envisioned, △ f< 3.75GHz）.

In signal power calculating part 2102-l（1≤l≤L）In, for from band filter portion 2101-1-l and band logical The output signal sequence signal calculated power of wave filter portion 2101-2-l.Here, as signal power, time signal can be calculated The power of each sampling of sequence, it is also possible to be divided into the block of certain length to export its interval signal power by signal sequence Sum.Further, in signal power calculating part 2102-l（1≤l≤L）In, by from the X of band filter portion 2101-1-l polarization The signal sequence of ripple and from band filter portion 2101-2-l Y polarized waves signal sequence as input value, but, in work( During rate is calculated, the sum of the power of X polarized waves and Y polarized waves can be exported, it is also possible to select the arbitrary of X polarized waves and Y polarized waves Individual result of calculation is simultaneously exported.

In training signal switching part 2103, will be from L kind signal power calculating part 2102-l（1≤l≤L, L >=2）'s Result of calculation selects the sequence with the value of maximum among the maximum of the signal power calculated in each sequence as input Arrange and export the sequence.For example, it is used as training sequence signal in the special frequency band signal sequence that Fig. 3 is have selected by transmitter In the case of, in receiver side, the maximum of signal power is bigger in signal power calculating part 2102-1, therefore, it is judged to connect Receive training sequence signal corresponding with signal power calculating part 2102-1.Now, training signal switching part 2103 is by signal power The output of calculating part 2102-1 to timing detection unit 2104 is exported, additionally, the special frequency band signal sequence that have selected Fig. 3 will be illustrated Information export to frequency offset computations portion 1103 and retardation calculating part 1104 as control information.

On the other hand, the feelings of training sequence signal are used as in the special frequency band signal sequence that Fig. 4 is have selected by transmitter Under condition, in receiver side, the maximum of signal power is bigger in signal power calculating part 2102-2, therefore, it is judged to receive Training sequence signal corresponding with signal power calculating part 2102-2.Now, training signal switching part 2103 is by signal power meter The output of calculation portion 2102-2 is exported to timing detection unit 2104, additionally, the special frequency band signal sequence that have selected Fig. 4 will be illustrated Information is exported as control information to frequency offset computations portion 1103 and retardation calculating part 1104.

Timing detection unit 2104 judges insertion training according to the output signal sequence from training signal switching part 2103 Position, and export its result as control information to memorizer 1101-1 and memorizer 1101-2.As the judgement of timing Method, exists to the value more than peak value or threshold value according to the performance number that each is sampled or each block is calculated or this both sides Temporal position carry out detecting the position for being used as training sequence signal presence（Regularly）.

In the reception signal of the impact that there is wavelength dispersion, as shown by list of references 1, in conventional situation Under, it is difficult to the synchronization of frame is obtained, but, in the present embodiment, even there is the reception signal of the impact of wavelength dispersion, The position of training signal can be detected, frame synchronization can be realized.

Figure 10 is the block diagram of the configuration example for illustrating the frequency offset computations portion 1103 in present embodiment.In the figure, 3101-1-l（1≤l≤L, L >=2）And 3101-2-l（1≤l≤L, L >=2）Represent band filter portion, 3102-l（1≤l≤ L, L >=2）Training signal power calculation portion is represented, 3103 represent training signal switching part, and 3104 represent side-play amount calculating part.Frequently Rate calculations of offset portion 1103 has 2 × L band filter portion 3101-1-1 ~ 3101-1-L, 3101-2-1 ~ 3101-2-L, instruction Practice signal power calculating part 3102-1 ~ 3102-L, training signal switching part 3103 and side-play amount calculating part 3104.

Band filter portion 3101-1-l（1≤l≤L, L >=2）To from memorizer 1101-1（Fig. 8）The X polarized waves of output Training sequence signal enter to exercise the band filter that the component of predetermined frequency band passes through（BPF）Process.Bandpass filtering Device portion 3101-2-l（1≤l≤L, L >=2）To from memorizer 1101-2（Fig. 8）The training sequence signal of the Y polarized waves of output enters Exercise the band filter that the component of predetermined frequency band passes through（BPF）Process.Here, the pin of frequency offset computations portion 1103 Possess the band filter portion 3101-1-l and band filter portion 3101- as L kinds BPF respectively to X polarized waves and Y polarized waves 2-l.Each L kind BPF is the wave filter that the component of signal of the training sequence signal for making different passes through, and is used in sender side The species of whole training sequence signals is arranged in correspondence with.

Training signal power calculation portion 3102-l（1≤l≤L, L >=2）For from band filter portion 3101-1-l（1≤l ≤ L, L >=2）With band filter portion 3101-2-l（1≤l≤L, L >=2）The signal of change signal power of output.Training signal Switching part 3103 will be from L kind training signal power calculation portion 3102-l（1≤l≤L, L >=2）Result of calculation as input, Select the training sequence signal of value maximum among the maximum with the power calculated in each training sequence signal simultaneously Export the training sequence signal.Additionally, training signal switching part 3103 exports selected training sequence signal, meanwhile, with instruction Practice signal switching part 2103（Fig. 9）The training sequence signal sent in sending side is similarly judged, using its result of determination as control Information output processed.Or, training signal switching part 3103 is using the control information from training signal switching part 2103 come from L kinds 1 kind is selected in training sequence signal, and exports selected training sequence signal.Side-play amount calculating part 3104 is according to from training letter The training sequence signal of number switching part 3103 output calculates frequency offset, and exports its result.

Band filter portion 3101-1-l（1≤l≤L, L >=2）With band filter portion 3101-2-l（1≤l≤L, L >= 2）, training signal power calculation portion 3102-l（1≤l≤L, L >=2）And the specific work of training signal switching part 3103 With above-mentioned band filter portion 2101-1-l（1≤l≤L, L >=2）And 2101-2-l（1≤l≤L, L >=2）, signal power calculate Portion 2102-l（1≤l≤L, L >=2）And the work of training signal switching part 2103 is identical, therefore, omit the description.

The specific work example of side-play amount calculating part 3104 is illustrated.For example, receive in light signal receiving It is original such as Fig. 3 institutes in the first special frequency band signal sequence in the case of first special frequency band signal sequence as Fig. 3 Show there is the peak value of the power of frequency spectrum in ± 15GHz like that.But, in the case where there is frequency shift (FS), in ± 15GHz+ △ f There is peak value in part, therefore, difference △ f is calculated according to the peak value for being detected, thus, in connecing for the impact that there is wavelength dispersion Frequency shift (FS) can be also calculated in the collection of letters number.For example, send become Fig. 3 frequency spectrum signal when receiving side 18GHz and- In the case that 12GHz detects peak value, being capable of basis（18-15）GHz or（-12-（-15））GHz estimates the frequency of △ f=3GHz Skew.

Figure 11 is the block diagram of the configuration example for illustrating the retardation calculating part 1104 in present embodiment.In the figure, 1201- 1 and 1201-2 represents signal dispenser, 1202-1-n and 1202-2-n（1≤n≤N, N >=2）Represent the n-th frequency bandpass filter Portion, 1203-1-n and 1203-2-n（1≤n≤N, N >=2）Represent power calculation portion, 1204-n（1≤n≤N, N >=2）Represent and close Ripple portion, 1205-n（1≤n≤N, N >=2）Averaging filter portion is represented, 1206 represent calculating part time delay.Retardation is calculated Portion 1104 has 2 signal dispensers 1201-1 and 1201-2,2 × N number of frequency bandpass filter portion 1202-1-1 ~ 1202-1- N, 1202-2-1 ~ 1202-2-N, 2 × N number of power calculation portion 1203-1-1 ~ 1203-1-N, 1203-2-1 ~ 1203-2-N, N number of conjunction Ripple portion 1204-1 ~ 1204-N, N number of averaging filter portion 1205-1 ~ 1205-N and calculating part time delay 1206.

Signal dispenser 1201-1 as input signal, makes the X polarized waves exported from wavelength dispersion compensation portion 1004-1 The input signal is replicated and branch is N number of identical signal sequence, to the n-th frequency bandpass filter portion 1202-1-n（1≤n≤ N, N >=2）Output.Signal dispenser 1201-2 is using the Y polarized waves exported from wavelength dispersion compensation portion 1004-2 as input letter Number, replicate the input signal and branch is N number of identical signal sequence, to the n-th frequency bandpass filter portion 1202-2-n（1 ≤ n≤N, N >=2）Output.

N-th frequency bandpass filter portion 1202-1-n（1≤n≤N, N >=2）To as from signal dispenser 1201-1 The frequency shift (FS) that the X polarized waves of output signal are calculated based on frequency offset computations portion 1103 is come compensating frequency deviation.Additionally, the N frequency bandpass filters portion 1202-1-n is based on and is exported with training sequence signal test section 1102 or frequency offset computations portion 1103 The related control information of special frequency band signal（The information of the species of special frequency band signal is shown）Believed using the special frequency band is made The process of number frequency bandpass filter for passing through passes through signal.After n-th frequency bandpass filter portion 1202-1-n will pass through Signal is exported as the result for processing to power calculation portion 1203-1-n.

N-th frequency bandpass filter portion 1202-2-n（1≤n≤N, N >=2）To as from signal dispenser 1201-2 The frequency shift (FS) that the Y polarized waves of output signal are calculated based on frequency offset computations portion 1103 is come compensating frequency deviation.Additionally, the N frequency bandpass filters portion 1202-2-n is based on and is exported with training sequence signal test section 1102 or frequency offset computations portion 1103 The related control information of special frequency band signal（The information of the species of special frequency band signal is shown）Believed using the special frequency band is made The process of number frequency bandpass filter for passing through passes through signal.After n-th frequency bandpass filter portion 1202-2-n will pass through Signal is exported as the result for processing to power calculation portion 1203-2-n.

Or, n-th frequency bandpass filter portion 1202-1-n, 1202-2-n（1≤n≤N, N >=2）Based on frequency shift (FS) The value of the frequency shift (FS) that calculating part 1103 is calculated and the species of special frequency band signal are moving（shift）Frequency bandpass filter Mid frequency after, pass through X polarized waves, Y polarized waves, and by the output of its result.Further, the n-th frequency bandpass filter portion 1202-1-n and the n-th frequency bandpass filter portion 1202-2-n（1≤n≤N, N >=2）Wave filter portion be to pass through identical frequency band Wave filter portion, with comprising according to the different frequency band of each sequence n special frequency band signal a part（For example, with specific frequency The frequency band of the bandwidth centered on the peak value of the power of the frequency spectrum of band signal more than the line width of light source）Or the mode of whole sets Frequency bandpass filter.

Power calculation portion 1203-1-n（1≤n≤N, N >=2）To what is exported from the n-th frequency bandpass filter portion 1202-1-n The sequence of X polarized waves exports its result to coupling part 1204-n according to each sampling calculated power value or the absolute value of amplitude.

Power calculation portion 1203-2-n（1≤n≤N, N >=2）To what is exported from the n-th frequency bandpass filter portion 1202-2-n The sequence of Y polarized waves exports its result to coupling part 1204-n according to each sampling calculated power value or the absolute value of amplitude.

Coupling part 1204-n（1≤n≤N, N >=2）The performance number of the X polarized waves to exporting from power calculation portion 1203-1-n Signal sequence and the signal sequence of performance number from the Y polarized waves of power calculation portion 1203-2-n outputs synthesized, export The result of synthesis.For example, the X polarized waves in m-th input of coupling part 1204-n are x_n（m）And Y polarized waves are y_n（m） In the case of, coupling part 1204-n is output as ax_n（m）+by_n（m）.Wherein, a and b are the arbitrary real number bigger than 0, Neng Gougen A and b changes are made according to information such as noise, interference, is made to defeated from power calculation portion 1203-1-n and power calculation portion 1203-2-n The X polarized waves for going out and the performance number of Y polarized waves carry out closing the ratio change of ripple.

For example, compared with the noise power of the leading section of the X polarized waves with receiving side the leading section of Y polarized waves noise work( In the case that rate is 4 times, a and b are adjusted to into a=2, b=1, so that noise power is equal.Thereby, it is possible to signal power to making an uproar Acoustical power is than maximum state composite signal sequence.In addition, it is also considered that because the impact of transmission path, leading section etc. polarizes in X The situation of delay difference is produced between ripple, Y polarized waves, thus, it is also possible in the q that staggers（Q is integer）Conjunction ripple is carried out after individual sampling. In this case, coupling part 1204-n is output as ax_n（m）+by_n（m-q）.As the determining method of q, it is also possible to connect in optical signal Timing test section, deflection are also equipped with receiving apparatus（skew）Adjustment portion, using the timing difference for calculating wherein as input value, Q can be adjusted so that for power calculation portion 1203-1-n, power calculation portion 1203-2-n output valve in certain fixed interval In exceed the value of threshold value or value when becoming maximum is overlapped.Further, the unit of hits be analog/digital conversion portion 1003-1 ~ The each signal in the time serieses after sampling in 1003-2.

By coupling part 1204-n（1≤n≤N, N >=2）Carry out the N number of signal sequence after conjunction ripple to be input to as input value In averaging filter portion 1205-n.Averaging filter portion 1205-n is respectively according to each sequence such as following formula being input into（1） Q continuous signal phase Calais is averaged like that.

[numerical expression 1]

Here, s_n（m）Represent the output signal of the n-th coupling part 1204-n in moment m, s '_n（m’）Represent equalization filtering Device portion 1205-n（1≤n≤N, N >=2）Output signal.By using averaging filter such that it is able to reduce noise, do Disturb.Additionally, by the way that Q is set as and special frequency band signal sequence identical signal number（It is this in the case where over-sampling is carried out The over-sampling several times of signal number）Such that it is able to will be from the n-th coupling part 1204-n（1≤n≤N, N >=2）The rectangular waveform of output For triangular wave, in time delay calculating part 1206, detection peak value becomes easy.

Time delay, calculating part 1206 was according to from N number of averaging filter portion 1205-n（1≤n≤N, N >=2）The sequence of output Row detect respectively each power maximum（Peak value）Sampling instant T during appearance_n.Time delay, calculating part 1206 was according to being detected Sampling time T_nBased on from training sequence signal test section 1102 or frequency offset computations portion 1103 special frequency band believe Number the related control information of species is come the wavelength dispersion amount that calculates the time difference between peak value or asked for according to the value and exports knot Really.

Here, N represents the individual of the peak power value in the frequency spectrum of the special frequency band signal sent by optical signal transmitter Number.For example, in the case where as shown in figure 3 there is peak power value in 2 special frequency band ± 15GHz, can calculate For N=2.Wherein, as long as N is more than 2, therefore, however it is not limited to it is above-mentioned.

Time delay calculating part 1206 calculate wavelength dispersion amount D ' in the case of, wavelength dispersion amount D ' can use kth Moment T at the peak value of coupling part 1204-k_kWith the moment T at the peak value of h coupling part 1204-h_hTime difference τ_k-hIt is such as following Following formula（2）Calculated like that.

[numerical expression 2]

In formula（2）In, c is the speed of light, λ for sending signal centre wavelength, B_k-hIt is from kth frequency bandpass filter Portion 1202-1-k（Or 1202-2-k）Mid frequency to h frequency bandpass filters portion 1202-1-h（Or 1202-2-h）In The bandwidth of frequency of heart.Where it is assumed that with kth frequency bandpass filter portion 1202-1-k（Or 1202-2-k）Compare, h frequency bands Bandpass filter portion 1202-1-h（Or 1202-2-h）It is higher frequency band by wave filter.

Additionally, B_k-hIt is from kth frequency bandpass filter portion 1202-1-k（Or 1202-2-k）Mid frequency to h frequency Rate band filter portion 1202-1-h（Or 1202-2-h）Mid frequency bandwidth, therefore, depend on special frequency band signal Species.Therefore, B_k-hIt is to be based on and the special frequency band from training sequence signal test section 1102 or frequency offset computations portion 1103 The species of signal related control information is calculating.

Time delay, calculating part 1206 can be used from N number of averaging filter portion 1205-n（1≤n≤N, N >=2）Input N number of sequence calculating 1 to maximum N（N-1）The time delay of/2, by the value selected among these time delays, Or the meansigma methodss or the wavelength dispersion amount that calculated according to the value of these time delays for calculating as output valve to wavelength color Scattered compensation section 1004-1 and wavelength dispersion compensation portion 1004-2 are exported.Further, in fact, the wavelength dispersion amount of output can also be Formula（2）No λ²Value（I.e. not divided by λ²）.This is because, such as following formula（3）As shown, by the meter of wavelength dispersion Calculation value is updated to weight W of each frequencies omega used in wavelength dispersion compensation portion 1004-1 and wavelength dispersion compensation portion 1004-2 （ω）When, it is multiplied by λ², therefore, in formula（2）Middle λ²It is cancelled and eliminates.That is, can actually not rely on λ²To calculate Wavelength dispersion compensation weight.

[numerical expression 3]

In formula（3）In, D ' represents the value of calculation of wavelength dispersion amount.

With regard to the light signal receiving in present embodiment, the optical signal for being received is split with polarization division portion 1001 For X polarized waves and Y polarized waves this 2 signal sequences, the optical electrical for coordinating the signal sequence number being partitioned into and possessing 2 sequences becomes Change portion 1002-1 ~ 1002-2, analog/digital conversion portion 1003-1 ~ 1003-2, wavelength dispersion compensation portion 1004-1 ~ 1004-2, letter Number dispenser 1201-1 ~ 1201-2, n-th frequency bandpass filter portion 1202-1-n, 1202-2-n（1≤n≤N, N >=2）, power Calculating part 1203-1-n, 1203-2-n（1≤n≤N, N >=2）, but it is also possible to only using the arbitrary of X polarized waves or Y polarized waves It is individual carrying out signal processing.In this case, as long as possessing above-mentioned each portion for 1 sequence, it is not necessary to coupling part 1204- n（1≤n≤N, N >=2）.Additionally, in the case where input signal to be assigned as the sequence of more than 3 with signal dispenser 1201, As long as possessing above-mentioned each portion of the amount of distributed sequence number and in coupling part 1204-n（1≤n≤N, N >=2）In carry out conjunction ripple .

In the amount of delaying calculating part 1104 in the present embodiment, possess average after coupling part 1204-1 ~ 1204-N Change wave filter portion 1205-1 ~ 1205-N, however, it is also possible to make their order be changed into contrary.In this case, as long as and power Calculating part 1203-1-1 ~ 1203-1-N, 1203-2-1 ~ 1203-2-N accordingly possesses 2 × N number of averaging filter portion, to work( The respective outputs of rate calculating part 1203-1-1 ~ 1203-1-N, 1203-2-1 ~ 1203-2-N average filtering, utilize afterwards Coupling part 1204-1 ~ 1204-N pair and identical frequency band（Sequence）The output in corresponding 2 × N number of averaging filter portion is closed Ripple.

Further, memorizer 1101-1 and memorizer 1101-2, training sequence signal test section 1102, frequency offset computations portion 1103 is not necessarily needs, for example, can detect training signal with the function of the outside of wavelength dispersion amount calculating part 1007 In the case of sequence and calculating frequency shift (FS), it is also possible to using its value, in the case where these values are known in advance, it is also possible to manually Setting.In the case where not possessing memorizer 1101-1 and memorizer 1101-2, training sequence signal test section 1102, frequency is inclined Calculating part 1103 is moved by the X polarized waves exported from wavelength dispersion compensation portion 1004-1 and wavelength dispersion compensation portion 1004-2 and Y poles The signal sequence for changing ripple calculates frequency shift (FS) as input.

Additionally, in the present embodiment, the species of special frequency band signal has been differentiated in receiving side, however, it is also possible in light The information of the special frequency band signal sequence for sending in advance is had in sender unit and light signal receiving, using the information To be operated.For example, ground transmission signal is tried in advance between optical signal transmitter and light signal receiving, also, The state of each device, propagation path is held in advance, and which special frequency band signal can be used thereby, it is possible to assurance in advance.At this In the case of, as long as the selection information based on total training sequence signal is in training sequence signal test section 1102, frequency shift (FS) The special frequency band signal sequence for representing only the selection information for obtaining in advance in calculating part 1103 and retardation calculating part 1104 Corresponding part work, can simplify circuit.

Specifically, in training sequence signal test section 1102（Fig. 9）In, band filter portion 2101-1-l（1≤l≤L, L ≥2）, band filter portion 2101-2-l（1≤l≤L, L >=2）And signal power calculating part 2102-l（1≤l≤L, L >= 2）For corresponding part.Additionally, in frequency offset computations portion 1103（Figure 10）In, band filter portion 3101-1-l（1≤l≤ L, L >=2）, band filter portion 3101-2-l（1≤l≤L, L >=2）And training signal power calculation portion 3102-l（1≤l ≤ L, L >=2）For corresponding part.In this case, it is also possible to do not possess the training letter in training sequence signal test section 1102 Training signal switching part 3103 in number switching part 2103 and frequency offset computations portion 1103, can simplify circuit.Or, training Training signal switching in training signal switching part 2103 and frequency offset computations portion 1103 in signal sequence test section 1102 Portion 3103 does not switch over and always only exports the input of part corresponding with selected training sequence signal.

Additionally, in training sequence signal test section 1102, by band filter portion 2101-1-l（1≤l≤L, L >=2） Can also be and training signal with multiple groups of band filter portion 2101-2-l and signal power calculating part 2102-l compositions The switching of switching part 2103 band filter and signal power calculating part that similarly switching passes through frequency.Additionally, inclined in frequency In moving calculating part 1103, by band filter portion 3101-1-l（1≤l≤L, L >=2）With band filter portion 3101-2-l and Multiple groups of training signal power calculation portion 3102-l compositions can also be in the same manner as the switching of training signal switching part 3103 Band filter and training signal power calculation portion of the switching by frequency.

Here, with reference to Figure 11, as an example, to using the special frequency band signal sequence shown in Fig. 3 as training signal Sequence and sending signal carry out it is time-multiplexed in the case of reception work illustrate.Further, N is set to 2.

In fig. 11, first, by light signal receiving receiver receive digital received signals in signal dispenser It is respectively allocated in 1201-1,1201-2 as 2 sequences.Then, first frequency band filter portion 1202-1-1,1202-2-1 Based on related to the species of the special frequency band signal from training sequence signal test section 1102 or frequency offset computations portion 1103 Information in X polarized waves, Y polarized waves carrying out frequency band restriction to obtain the signal of the 15GHz of high frequency side respectively, and will Its result output.Figure 12 is to illustrate first frequency band filter portion 1202-1-1 in present embodiment to carrying out frequency shift (FS) Input after compensation receives the skeleton diagram of the example of the frequency band restriction that signal is carried out.In the figure, transverse axis represents frequency, longitudinal axis table Show amplitude.As going out as shown in the drawing, after first frequency band filter portion 1202-1-1 is to carrying out frequency offset compensation Input reception signal is used will（15-W）GHz is arrived（15+W）GHz is set to the band filter of bandwidth 2W of passband to enter line frequency Band is limited, and exports its result.First frequency band filter portion 1202-2-1 also carries out same process to Y polarized waves.

Similarly, second frequency band filter portion 1202-1-2,1202-2-2 is respectively in X polarized waves, Y polarized waves Obtain the signal of -15GHz of lower frequency side and carry out frequency band restriction, and export its result.Figure 13 is illustrated in present embodiment Second frequency band filter portion 1202-1-2 to carrying out frequency offset compensation after input receive signal carry out frequency band limit The skeleton diagram of the example of system.In the figure, transverse axis represents frequency, and the longitudinal axis represents amplitude.As going out as shown in the drawing, the second frequency Rate band filter portion 1202-1-2 to carrying out frequency offset compensation after input receive signal using will（-15-W）GHz is arrived（- 15+W）GHz is set to the band filter of bandwidth 2W of passband to carry out frequency band restriction, and exports its result.Second frequency band Bandpass filter portion 1202-2-2 also carries out same process to Y polarized waves.

Here, W is the arbitrary value bigger than 0.Become big by making W, so as to, even if due to frequency shift (FS), phase offset etc., Specific frequency reception signal deviates from mid frequency, it is also possible to be operated.On the contrary, diminished by making W, thus, it is possible to The component such as noise, interference components beyond special frequency band signal is reduced, therefore, estimated accuracy is improved.

Signal sequences of the power calculation portion 1203-1-1 for the output result of first frequency band filter portion 1202-1-1 The absolute value for coming calculated power value or amplitude according to each sampling is arranged, its result is exported to coupling part 1204-1.Similarly, work( Rate calculating part 1203-2-1 is directed to the signal sequence of the output result of first frequency band filter portion 1202-2-1 according to each Sampling carrys out the absolute value of calculated power value or amplitude, and its result is exported to coupling part 1204-1.Here, by power calculation portion The input signal of the n sampling instants of 1203-1-1,1203-2-1 is set to a（n）In the case of, power calculation portion 1203-1-1, The output valve Wei ∣ a of 1203-2-1（n）∣²Huo ∣ a（n）∣.Wherein , ∣ x ∣ represent the absolute value of plural x.

Similarly, power calculation portion 1203-1-2 is for the output result of second frequency band filter portion 1202-1-2 Signal sequence carrys out calculated power value according to each sampling, and its result is exported to coupling part 1204-2.Power calculation portion 1203-2- 2 calculate power for the signal sequence of the output result of second frequency band filter portion 1202-2-2 according to each sampling Value, its result is exported to coupling part 1204-2.

Coupling part 1204-1 using the sequence exported from power calculation portion 1203-1-1 and power calculation portion 1203-2-1 as It is input into carry out conjunction ripple, and exports its result.Similarly, coupling part 1204-2 will be from power calculation portion 1203-1-2 and energy meter The sequence of calculation portion 1203-2-2 outputs carries out conjunction ripple as input, and exports its result.

Averaging filter portion 1205-1 averages the sequence exported from coupling part 1204-1 as input, and Export its result.Similarly, averaging filter portion 1205-2 enters the sequence exported from coupling part 1204-2 as input Row equalization, and export its result.

Figure 14 is the output knot for illustrating the first averaging filter portion 1205-1 and the second averaging filter portion 1205-2 The figure of fruit.In the figure, transverse axis represents the sampling time, and the longitudinal axis represents power.Calculating part 1206 will be average from first time delay Change the sequence of wave filter portion 1205-1 and the second averaging filter portion 1205-2 outputs as input, as illustrated in FIG. 14 that Sampling instant T when sample detects that power becomes maximum value in each sequence₁With sampling instant T₂, and calculate its time difference τ_2-1= T₂-T₁.It is further possible to using above-mentioned time difference τ_2-1Based on formula（2）To calculate wavelength dispersion amount D '.

The wavelength dispersion amount that calculate using special frequency band signal sequence can as described above be done.Further, as specific Band signal and the special frequency band signal sequence illustrated in Fig. 4 is carried out as training sequence signal and sending signal time-multiplexed In the case of, first frequency band filter portion 1202-1-1,1202-2-1 be based on from training sequence signal test section 1102 or frequency offset computations portion 1103 special frequency band signal the related information of species, respectively in X polarized waves, Y polarized waves In, in order to obtain the signal of the 7.5GHz of high frequency side and to carrying out frequency offset compensation after input receive signal using will （7.5-W）GHz is arrived（7.5+W）GHz is set to the band filter of bandwidth 2W of passband to carry out frequency band restriction, and by its result Output.Similarly, second frequency band filter portion 1202-1-2,1202-2-2 respectively in X polarized waves, Y polarized waves in order to Obtain-the 7.5GHz of lower frequency side signal and to carrying out frequency offset compensation after input receive signal using will（-7.5-W） GHz is arrived（-7.5+W）GHz is set to the band filter of bandwidth 2W of passband to carry out frequency band restriction, and by its result output.

In the special frequency band signal sequence that will be illustrated in Fig. 4 as in the case of training sequence signal, counted by time delay Time difference τ that calculation portion 1206 calculates_2-1=T₂-T₁With the special frequency band signal sequence that will be illustrated in Fig. 3 as training sequence signal Situation is compared, and the bandwidth between 2 peak values of frequency spectrum is changed into half, but, due to formula（2）In bandwidth B_2-1Also it is changed into half, institute With final wavelength dispersion amount D estimated ' become equal.

Further, as training sequence signal, insert before and after special frequency band signal sequence power concentrate merely on it is specific Second special frequency band signal sequence of the different characteristic frequency of band signal sequence, thus, prevents to special frequency band signal sequence The interference caused by the sending signal sequence before and after training signal of the frequency band for using, therefore, as illustrated in FIG. 14 as The peak value of performance number clearly occurs, and sampling instant T when power becomes maximum value can be correctly detected₁With sampling instant T₂。 Additionally, setpoint frequency band filter is so that in the frequencies of first frequency band filter portion 1202-1-1 and 1202-2-1 and second The second special frequency band signal sequence is removed in rate band filter portion 1202-1-2 and 1202-2-2, thereby, it is possible to prolong in calculating Late during time difference, the signal of the second special frequency band signal sequence slightly before and after a while of special frequency band signal sequence is removed, only carried The first special frequency band signal sequence is taken out, therefore, the estimated accuracy of wavelength dispersion is improved.Further, replacing the second special frequency band letter Number sequence and set between dead space, i.e. the not interval of sending signal, also obtain same effect.

As above-mentioned the n-th shown frequency bandpass filter portion 1202-1-n and 1202-2-n（n=1, 2, …, N）'s Band filter, can be using general band logicals such as rectangular filter, nyquist filter, Hanning window, kaiser window, Hamming windows Wave filter.Additionally, in usage frequency band filter, using fast Fourier transform（FFT）Or discrete Fourier transform （DFT）Signal sequence is transformed to after frequency-region signal, is carried out in a frequency domain using the filtering of band filter, using quick Fu In leaf inverse transformation（IFFT）Or inverse discrete Fourier transform（IDFT）Time signal is transformed to, thereby, it is possible to seek the height of computing Speedization.

Further, with regard to band filter portion 2101-1-1 ~ 2101-2-L, band filter portion 3101-1-1 ~ 3101-2-L, Also in the same manner as the band filter of the n-th frequency bandpass filter portion 1202-1-n and 1202-2-n, carry out using above-mentioned general Band filter filtering, or, after signal sequence to be transformed to frequency-region signal using FFT or DFT, enter in a frequency domain Filtered signal sequence is transformed to time signal, thus, energy by row using the filtering of band filter using IFFT or IDFT Enough seek the high speed of computing.

Further, realizing the n-th frequency bandpass filter portion 1202- of retardation calculating part 1104 using FFT and IFFT 1-n and 1202-2-n, the band filter portion 3101-1-1 ~ 3101-L, 3101-2-1 ~ 3101- in frequency offset computations portion 1103 In the case of 2-L, as illustrated in the above description, as long as frequency offset computations portion 1103 and retardation calculating part 1104 The signal for being stored by 1101-1 and 1101-2 bufferings is used only in the interval of the insertion cycle Ns of training sequence signal counting Calculate frequency offset and retardation.Therefore, using the situation that FFT and IFFT can be realized with butterfly operation, using FFT FFT size of the size than original application（Or points）Little FFT or IFFT thereby, it is possible to delay allowance and is cut repeating to process Subtract circuit scale.Further, in the n-th frequency bandpass filter portion 1202-1-n and 1202-2-n of retardation calculating part 1104（n= 1, 2, …, N）, frequency offset computations portion 1103 band filter portion 3101-1-1 ~ 3101-L, 3101-2-1 ~ 3101-2- In L, sharing carries out the circuit of FFT and carries out the circuit of IFFT, thus, it is also possible to cut down circuit scale.

Hereinafter, as an example, to using FFT and IFFT in order to be filtered in a frequency domain in the case of wavelength The configuration example of dispersion measure calculating part 1007, frequency offset computations portion 1103 and retardation calculating part 1104 is illustrated.

Figure 15 is to illustrate to use the wavelength dispersion amount in the case of FFT and IFFT to calculate to be filtered in a frequency domain The block diagram of the configuration example in portion 1007.Wavelength dispersion amount calculating part 1007 shown in the figure have memorizer 1101-1 and 1101-2, Training sequence signal test section 1102, frequency offset computations portion 1103, retardation calculating part 1104 and FFT portions 1501-1 and 1501-2.In the structure of the wavelength dispersion amount calculating part 1007 shown in the figure, with the wavelength dispersion amount calculating part shown in Fig. 8 1007 structure difference is to the addition of FFT portions 1501-1 and 1501-2.Further, being omitted for saying for common each portion It is bright.

The signal sequence that FFT portions 1501-1 will be stored in memorizer 1101-1 carries out FFT as input, by the signal Sequence transformation is the signal of frequency domain.FFT portions 1501-1 is by the signal of the frequency domain obtained by conversion to frequency offset computations portion 1103 and retardation calculating part 1104 export.In the same manner as FFT portions 1501-1, FFT portions 1501-2 will be stored in memorizer 1101- Signal sequence in 2 carries out FFT as input, and the signal sequence is transformed to into the signal of frequency domain.FFT portions 1501-2 will pass through The signal of the frequency domain that conversion is obtained is exported to frequency offset computations portion 1103 and retardation calculating part 1104.That is, shown in Figure 15 Wavelength dispersion amount calculating part 1007 in, frequency offset computations portion 1103 and retardation calculating part 1104 using the signal of frequency domain as Input is operated.

Figure 16 is to illustrate the frequency offset computations portion used to be filtered in a frequency domain in the case of FFT and IFFT The block diagram of 1103 configuration example.Frequency offset computations portion 1103 shown in the figure has 2 × L frequency domain band filter portion 3501-1-1 ~ 3501-1-L, 3501-2-1 ~ 3501-2-L, 2 × L IFFT Department 3502-1-1 ~ 3502-1-L, 3502-2-1 ~ 3502-2-L, L training signal power calculation portion 3102-1 ~ 3102-L, training signal switching part 3103 and side-play amount are calculated Portion 3104.

In the structure in the frequency offset computations portion 1103 shown in the figure, with the frequency offset computations portion 1103 shown in Figure 10 Structure difference be, replace band filter portion 3101-1-1 ~ 3101-1-L and there is frequency domain band filter portion 3501-1-1 ~ 3501-1-L and IFFT Department 3502-1-1 ~ 3502-1-L, and replace band filter portion 3101-2-1 ~ 3101- 2-L and there is frequency domain band filter portion 3501-2-1 ~ 3501-2-L and IFFT Department 3502-2-1 ~ 3502-2-L.Further, omitting For the explanation in common each portion.

Frequency domain band filter portion 3501-1-l（1≤l≤L, L >=2）To from FFT portions 1501-1（Figure 15）The X poles of output The frequency component for changing the sequence of ripple is entered to exercise the band filter that the component of predetermined frequency band passes through in a frequency domain（BPF）'s Process.Frequency domain band filter portion 3501-2-l（1≤l≤L, L >=2）To from FFT portions 1501-2（Figure 15）The Y polarized waves of output The frequency component of sequence enter to exercise the band filter that the component of predetermined frequency band passes through in a frequency domain（BPF）Place Reason.As frequency domain band filter the portion 3501-1-l and 3501-2-l of L kinds BPF（1≤l≤L, L >=2）With band filter portion 3101-1-l and 3101-2-l（1≤l≤L, L >=2）Similarly, the component of signal to make different training sequence signals passes through Wave filter, is arranged in correspondence with the species of the whole training sequence signals used in sender side.

IFFT Department 3502-1-l（1≤l≤L, L >=2）Respectively to from corresponding frequency domain band filter portion 3501-1-l Frequency component after the BPF of the sequence of the X polarized waves of output carries out IFFT, and the frequency component is transformed to into the signal of time domain. IFFT Department 3502-1-l is respectively exported the signal of the time domain obtained by conversion to training signal power calculation portion 3102-l. IFFT Department 3502-2-l（1≤l≤L, L >=2）Respectively to from the Y poles of corresponding frequency domain band filter portion 3501-2-l outputs Frequency component after the BPF of the sequence for changing ripple carries out IFFT, and the frequency component is transformed to into the signal of time domain.IFFT Department 3502- 2-l is respectively exported the signal of the time domain obtained by conversion to training signal power calculation portion 3102-l.

Figure 17 is to illustrate the retardation calculating part used to be filtered in a frequency domain in the case of FFT and IFFT The block diagram of 1104 configuration example.Retardation calculating part 1104 shown in the figure have 2 signal dispensers 1201-1 and 1201-2, The n-th frequency bandpass filter of 2 × N number of frequency domain portion 1801-1-1 ~ 1801-1-N and 1801-2-1 ~ 1801-2-N, 2 × N number of IFFT Portion 1802-1-1 ~ 1802-1-N and 1802-2-1 ~ 1802-2-N, 2 × N number of power calculation portion 1203-1-1 ~ 1203-1-N and 1203-2-1 ~ 1203-2-N, N number of coupling part 1204-1 ~ 1204-N, N number of averaging filter portion 1205-1 ~ 1205-N and Time delay calculating part 1206.

Knot in the structure of the retardation calculating part 1104 shown in the figure, with the retardation calculating part 1104 shown in Figure 11 Structure difference is to replace the n-th frequency bandpass filter portion 1202-1-n（1≤n≤N, N >=2）And there is the frequency of frequency domain n-th Band filter portion 1801-1-1 ~ 1801-1-N and IFFT Department 1802-1-1 ~ 1802-1-N and replacement the n-th frequency band logical filter Ripple device portion 1202-2-n（1≤n≤N, N >=2）And have the n-th frequency bandpass filter of frequency domain portion 1801-2-1 ~ 1801-2-N and IFFT Department 1802-2-1 ~ 1802-2-N.Further, being omitted for the explanation in common each portion.

Frequency domain the n-th frequency bandpass filter portion 1801-1-n（1≤n≤N, N >=2）To as from signal dispenser The signal sequence of the X polarized waves of the output signal of 1201-1, i.e. by FFT portions 1501-1（Figure 15）Frequency after the FFT for carrying out point The frequency shift (FS) that amount is calculated based on frequency offset computations portion 1103 is come compensating frequency deviation.Additionally, the filter of the n-th frequency of frequency domain band logical Ripple device portion 1801-1-n is based on the specific frequency exported with training sequence signal test section 1102 or frequency offset computations portion 1103 The related control information of band signal（The information of the species of special frequency band signal is shown）Using making what the special frequency band signal passed through The process of frequency bandpass filter passes through signal.The n-th frequency bandpass filter of frequency domain portion 1801-1-n is by the signal after passing through Export to IFFT Department 1802-1-n as the result for processing.

Frequency domain the n-th frequency bandpass filter portion 1801-2-n（1≤n≤N, N >=2）To as from signal dispenser The signal sequence of the Y polarized waves of the output signal of 1201-2, i.e. by FFT portions 1501-2（Figure 15）Frequency after the FFT for carrying out point The frequency shift (FS) that amount is calculated based on frequency offset computations portion 1103 is come compensating frequency deviation.Additionally, the filter of the n-th frequency of frequency domain band logical Ripple device portion 1801-2-n is based on the specific frequency exported with training sequence signal test section 1102 or frequency offset computations portion 1103 The related control information of band signal（The information of the species of special frequency band signal is shown）Using making what the special frequency band signal passed through The process of frequency bandpass filter passes through signal.The n-th frequency bandpass filter of frequency domain portion 1801-2-n is by the signal after passing through Export to IFFT Department 1802-2-n as the result for processing.

Or, the n-th frequency bandpass filter of frequency domain portion 1801-1-n, 1801-2-n（1≤n≤N, N >=2）Based on frequency The travel frequency band logical filter in a frequency domain of the value of the frequency shift (FS) that calculations of offset portion 1103 calculates and the species of special frequency band signal The mid frequency of ripple device（That is, mobile FFT indexes）Afterwards, pass through X polarized waves, Y polarized waves, and export its result.Further, frequency Domain the n-th frequency bandpass filter portion 1801-1-n and frequency domain the n-th frequency bandpass filter portion 1801-2-n（1≤n≤N, N >=2） Wave filter portion be wave filter portion by identical frequency band, to believe comprising the special frequency band according to the different frequency band of each sequence n Number a part（For example, the band centered on the peak value of the power of the frequency spectrum of special frequency band signal more than the line width of light source Wide frequency band）Or the mode of whole setpoint frequency band filter in a frequency domain.

IFFT Department 1802-1-n（1≤n≤N, N >=2）To from corresponding frequency domain the n-th frequency bandpass filter portion 1801- The frequency component of the sequence of the X polarized waves of 1-n outputs carries out IFFT, and the frequency component is transformed to into the signal of time domain.IFFT Department 1802-1-n exports the signal of the time domain obtained by conversion to power calculation portion 1203-1-n.IFFT Department 1802-2-n（1≤ N≤N, N >=2）Frequency to the sequence of the Y polarized waves from corresponding the n-th frequency bandpass filter of frequency domain portion 1801-2-n outputs Rate component carries out IFFT, and the frequency component is transformed to into the signal of time domain.IFFT Department 1802-2-n by by conversion obtain when The signal in domain to power calculation portion 1203-2-n is exported.

Further, in the FFT portions 1501-1 and 1501-2 of wavelength dispersion amount calculating part 1007, it is also possible to which sharing carries out FFT The circuit of computing（Operational part）.Thereby, it is possible to cut down the circuit scale of wavelength dispersion amount calculating part 1007.In addition it is also possible to altogether With IFFT Department 3502-1-l and 3502-2-l that carry out frequency offset computations portion 1103（1≤l≤L, L >=2）And delay gauge IFFT Department 1802-1-n and 1802-2-n in calculation portion 1104（1≤n≤N, N >=2）Some or all of IFFT computings electricity Road（Operational part）.Thereby, it is possible to cut down the circuit scale of frequency offset computations portion 1103, retardation calculating part 1104.Additionally, FFT portions 1501-1 and 1501-2, IFFT Department 3502-1-l and 3502-2-l（1≤l≤L, L >=2）And IFFT Department 1802-1-n And 1802-2-n（1≤n≤N, N >=2）In, it is also possible to sharing carries out the circuit of common computing in the computing of FFT and IFFT.

Additionally, by using structure as shown in Figure 15, so as to training sequence signal test section 1102 is to training signal sequence The on position of row is detected, to memorizer 1101-1 and memorizer 1101-2 output control signals, so as to be based on detect Training sequence signal on position and only buffers packet containing training sequence signal interval and its before and after interval signal sequence Row.Therefore, as long as FFT portions 1501-1 and 1501-2, frequency offset computations portion 1103 and retardation calculating part 1104 are only used The signal of 1101-1 and 1101-2 bufferings is stored by the interval of the insertion cycle Ns of training sequence signal carrying out FFT simultaneously And calculating frequency offset and retardation.Now, the insertion cycle Ns of training is bigger relative to the signal sequence being buffered, Then can more make the work(for realizing FFT portions 1501-1 and 1501-2, frequency offset computations portion 1103 and retardation calculating part 1104 The work clock of the synchronous circuit of energy and the work clock of the synchronous circuit of the function of realizing training sequence signal test section 1102 Compare the frequency for being changed into low, as a result, can realize that low power consumption, circuit scale are cut down.Further, as long as according to every U（U >=2, U is Integer）Individual frame come in the case of estimating frequency offset and retardation, and according to the situation phase estimated per 1 frame Than, work clock can be reduced, can realize that further low power consumption, circuit scale are cut down.

Averaging filter portion 1205-n shown in above-mentioned exports Q continuous signal sequence phase adduction, thereby, it is possible to Mitigate the estimation difference caused due to noise, interference components, but it is also possible to using other methods.For example, by using maximum Power and moment near value is calculating expected value, it is also possible to improve precision.

In above-mentioned shown calculating part time delay 1206, sampling instant when having used power to become maximum value, but Be, it is also possible to set arbitrary threshold value, using power exceed the threshold value moment or when more than after be less than threshold value when when Or the both sides.In this case, there is following method：High fdrequency components and low frequency component pair compared with peak value more X% when Carve position to be compared to determine its time difference.

Additionally, also including the signal and interference, noise beyond alternating signal in by the component of signal of band filter Component.This is because the component of the passband of band filter being there is also in data signal and being because in optical noise There is the component of the passband of band filter.Therefore, to not producing the region of peak value（Data signal region）In background make an uproar Sound and peak value detected, in high fdrequency components and low frequency component to rising to the when meta of the X% of peak value on the basis of background noise Put/time location of X% that peak value is dropped on the basis of noise floor is compared, thus, it is also possible to detect time delay.

Additionally, being calculated in time delay using the multiple reception signals comprising training sequence signal according to each cycle Ns Multiple time delays are calculated in portion 1206, value is averaged and is exported as output valve, thereby, it is possible to reduce noise, interference Component, precision is improved.Further, using power and the moment the two values come calculate peak value appearance moment expected value, thus, Being capable of the computing relay time.

Further, since with polarized mode dispersion（PMD）Headed by propagation path in frequency adjusting amplitude of vibration, receiving power root It is different according to frequency component, therefore, prepare the special frequency band signal sequence of more than 2, for example, received signal power is determined to making an uproar Acoustical power ratio（SNR）, signal power etc., using SNR, signal power etc. for maximum sequence as training sequence signal carrying out sending out Send and also may be used.Further, since the frequency characteristic of the leading section of the simulation such as power amplifier, ADC, DAC, the amplitude decay of high fdrequency components Or group delay is produced, therefore, will be present in the special frequency band signal sequence of the frequency band of the impact for not being subject to these frequency characteristics As training sequence signal, thereby, it is possible to suppress wavelength dispersion amount calculating part 1007 in computational accuracy deterioration.

Additionally, when transmission path is designed, considering after the impact of the interference ripple of adjacent channel, will not be subject to The special frequency band signal sequence of the impact of interference is transmitted as training sequence signal also may be used.

Additionally, in the above description, 1 is selected from multiple special frequency band signal sequences and as training signal sequence Arrange to be transmitted, but, it is not necessarily required to be set to 1.The sequence of more than 2 is selected in sending side and as training signal Sequence carries out above-mentioned reception signal processing being transmitted in receiving side to each, calculates wavelength dispersion, and any one is calculated Or the meansigma methodss etc. of whole estimated result also may be used as the value of calculation of wavelength dispersion as a result.

Additionally, in wavelength dispersion amount calculating part 1007, the time delay of retardation calculating part 1104 measures and special frequency band Bandwidth between the peak value of the frequency spectrum of signal is becoming proportionately larger, therefore, special frequency band signal sequence is changed according to wavelength dispersion amount Row also may be used.For example, in the case where needing to calculate big wavelength dispersion amount in long range propagation, by using the peak value of frequency spectrum Between the little special frequency band signal sequence of bandwidth, so as to amount time delay diminishes, with this concomitantly, in the signal sequence of receiving side In diminish comprising the region of training sequence signal, therefore, it is possible to cut down the operand of wavelength dispersion amount calculating part 1007.The opposing party Face, in the case of relatively short-distance transmission or by using dispersion shifted optical fiber（DSF）And the wavelength dispersion amount for calculating In the case of smaller, by using frequency spectrum peak value between the roomy special frequency band signal sequence of band such that it is able to raising is estimated Meter precision.

Further, in the above description, in the n-th frequency bandpass filter portion 1202-1-n and 1202-2-n（1≤n≤N, N >= 2）Or in the n-th frequency bandpass filter of frequency domain portion 1801-1-n and 1801-2-n, based on from training sequence signal test section 1102 or the related control information of special frequency band signal of the output of frequency offset computations portion 1103（The kind of special frequency band signal is shown The information of class）To make the special frequency band signal that Filtering Processing has been carried out by way of.But, by the use of Filtering Processing make remove as Band component beyond the band component of the special frequency band signal of training sequence signal passes through, thereby, it is possible to estimating noise power. This is because, it is the property of special frequency band signal as training sequence signal, in training sequence signal interval, except power collection In specific frequency component beyond, there is no component of signal, only exist noise.

When above-mentioned noise power is estimated, in the case of the structure of Figure 11, the n-th frequency bandpass filter portion 1202-1-n Process, power are filtered with 1202-2-n to make noise component(s) by way of, in the way of i.e. to remove special frequency band signal Outputs of the calculating part 1203-1-n and 1203-2-n to the n-th frequency bandpass filter portion 1202-1-n and 1202-2-n calculates each The power of sampling, coupling part 1204-n carries out polarity combination using the output of power calculation portion 1203-1-n and 1203-2-n, prolongs Late Time Calculation portion 1206 is counted using the performance number of each sampling after the polarity combination calculated in coupling part 1204-n Calculate noise power.Further, when noise power is calculated, it is also possible to do not possess averaging filter portion 1205-n.Additionally, when postponing Between calculating part 1206 possess the function of calculating wavelength dispersion amount and the function of calculating noise power, therefore, it is possible to referred to as transmission road Footpath information calculating part.

Similarly, in the case of the structure of Figure 17, the n-th frequency bandpass filter portion 1801-1-n and 1801-2-n so that Noise component(s) is filtered processs by way of, in the way of i.e. to remove special frequency band signal, IFFT Department 1802-1-n with Outputs of the 1802-2-n to the n-th frequency bandpass filter portion 1801-1-n and 1801-2-n carries out IFFT, power calculation portion 1203- Outputs of the 1-n and 1203-2-n to IFFT Department 1802-1-n and 1802-2-n calculates the power of each sampling, coupling part 1204-n Carry out polarity combination using the output of power calculation portion 1203-1-n and 1203-2-n, time delay, calculating part 1206 was using existing The performance number of each sampling after the polarity combination calculated in coupling part 1204-n is calculating noise power.Further, calculating During noise power, it is also possible to do not possess averaging filter portion 1205-n.

Hereinafter, to carrying out the calculating of noise power and signal power and using the noise power and signal for calculating The signal of power is to noise power ratio（SN ratios）The SN of calculating illustrate than computing device.Further, hereinafter, envisioning SN ratios Computing device is arranged on the structure of the outside of light signal receiving to illustrate, and however, it can be SN than calculating dress Put the structure of the inside for being arranged on light signal receiving.

Calculated based on the signal of telecommunication exported from memorizer 1101-1 and 1101-2 than computing device 4 in the SN of following explanation The SN ratios of the optical signal in coherent communication system.The SN ratios are the value related to data are sent.

Further, when SN exports SN ratios than computing device 4, using the signal of telecommunication or optical signal which transmitting SN ratios all Can be with.

Figure 20 is to illustrate block diagrams of the SN in present embodiment than the configuration example of computing device 4.SN possesses than computing device 4 Coupling part 46, signal power calculating part 47, special frequency band component of signal removing unit 48, noise power calculation portion 49 and SN ratios Calculating part 50.These each portions are corresponding as described below with each portion in Figure 11.That is, coupling part 46 is corresponding with coupling part 1204-n, Signal power calculating part 47 or noise power calculation portion 49 are corresponding with power calculation portion 1203-1-n and 1203-2-n, special frequency band Component of signal removing unit 48 is corresponding with the n-th frequency bandpass filter portion 1202-1-n and 1202-2-n, SN than calculating part 50 with prolong Slow Time Calculation portion 1206 correspondence.Further, in Figure 11 and Figure 20, coupling part 46 is different with the position of coupling part 1204-n, but It is, it is different from the situation of computing relay time in the case where noise power is calculated, power is calculated, therefore, configuration is closed The position in ripple portion be the frequency domain before IFFT computings and the time domain after IFFT computings which can, be filtered after ripple is closed Process and power calculation is processed and can more cut down circuit scale.Hereinafter, illustrating in the case of the structure of Figure 20.

The signal and the signal from FFT portions 1501-2 from FFT portions 1501-1 is input into coupling part 46.For being input to The signal of the frequency domain in coupling part 46, due in memorizer 1101-1 and 1101-2 or time-domain window portion 1105-1 and 1105-2 In be extracted and special frequency band signal sequence（Training sequence signal）Corresponding digital signal, so, become not comprising transmission number According to the signal of sequence.That is, in the signal of the frequency domain being input into, the frequency component comprising special frequency band signal sequence and noise Frequency component.The signal of 46 pairs of frequency domains being sequentially output from FFT portions 1501-1 of coupling part and it is sequentially output from FFT portions 1501-2 The signal of frequency domain carries out conjunction ripple.Coupling part 46 will carry out signal obtained from conjunction ripple to signal power calculating part 47 and special frequency band Component of signal removing unit 48 is exported.Further, in the structure for not possessing FFT portions 1501-1 and 1501-2 as Fig. 8, Figure 18 In the case of, can be by possessing fft circuit respectively and exporting this for the output from memorizer 1101-1 and 1101-2 It is input in coupling part 46 to realize.Additionally, each frequency component can be directed at than the method for the conjunction ripple in computing device as SN Phase place and be separately summed, it is also possible to calculate the power of each frequency component and be separately summed.

Signal power calculating part 47 is calculated as special frequency band signal sequence based on the signal exported from coupling part 46 The signal power of power.Signal power calculating part 47 exports the performance number of the signal power for calculating than calculating part 50 to SN.

Special frequency band component of signal removing unit 48 removes special frequency band signal sequence from the signal exported from coupling part 46 Component, the signal for eliminating the component of special frequency band signal sequence is exported to noise power calculation portion 49.With regard to specific frequency The component of the special frequency band signal sequence in band signal component removing unit 48, is concentrated due to the power of special frequency band signal sequence Frequency is known, thus it is possible to be removed by using band filter etc..Further, special frequency band component of signal removing unit Signal processing in 48 can be carried out in a frequency domain, it is also possible to be carried out in the time domain.Noise power calculation portion 49 is based on from specific The signal of the output of subband-signal component removing unit 48 is calculating the noise power of the power as noise.Noise power calculation portion 49 The performance number of the noise power for calculating is exported to SN than calculating part 50.Further, special frequency band component of signal removing unit 48 Can be based on the value of calculation of the frequency shift (FS) from frequency offset computations portion 1103 come correcting frequency shift.

Noise power and the institute of signal power calculating part 47 that SN is calculated than calculating part 50 based on noise power calculation portion 49 The signal power of calculating is calculating the SN ratios of the ratio as power and the noise power for sending data sequence.SN is more defeated than calculating part 50 Go out and represent that the SN of the SN ratios for calculating compares signal.

SN than the calculating of the SN ratios in calculating part 50 be by calculate the SN of special frequency band signal sequence than it is laggard Row conversion come calculate send data sequence SN ratios and carry out.As the method for conversion, for example, by special frequency band signal sequence With the power ratio of the time per unit for sending data sequence as conversion coefficient, by conversion coefficient and special frequency band signal sequence SN than be multiplied, thus, calculate send data sequence SN ratios.The derivation of conversion coefficient is, for example, to compare to sending data sequence Power when carrying out time division multiplex with special frequency band signal sequence is asking in advance.Or, in simulations, based on transmission data Sequence length and special frequency band signal sequence length ratio also may be used deriving conversion coefficient.Or, will be using spectrum analyzer etc. Compared with the SN ratios that the SN ratios of the high precision for determining are calculated with SN than computing device 4, carry out counting SN than computing device 4 The calibration of the SN ratios of calculation, thus, determines that conversion coefficient also may be used.

Additionally, SN replaces the power of special frequency band signal sequence and uses from wavelength dispersion compensation portion than calculating part 50 The signal of each input of 1004-1 and 1004-2（Hereinafter referred to as the first digital signal sequences and the second digital signal sequences） Power also may be used calculating SN ratios.Or, SN is based on the specially appointed area of training sequence signal test section 1102 than calculating part 50 Between from the first digital signal sequences and the second digital signal sequences extract comprising send data sequence component digital signal, The power for sending data sequence is calculated according to the digital signal for extracting, is replaced the power of special frequency band signal sequence and is used The power for sending data sequence also may be used calculating SN ratios.In this case, due to having used except the work(of special frequency band signal sequence Power beyond rate, so, when the power using the first digital signal sequences and the second digital signal sequences compared with, Neng Gouti In high precision.

Further, it is also possible to the electricity after being converted using the power or optical electrical of the optical signal incided in light signal receiving The power of signal is asking for the power of the first digital signal sequences and the second digital signal sequences.With regard in light signal receiving The power ratio for sending DS and special frequency band signal sequence in the optical signal of middle reception, the power for sending data sequence is accounted for The optical signal for being received or the major part of the power of the signal of telecommunication, thus, for example, sending data sequence can also be counted as incidence To the optical signal in optical electrical transformation component 1002-1 and 1002-2.Can made an uproar by deducting from resulting optical signal power The noise power calculated in acoustical power calculating part 49 is asking for signal power.

As described above, the signal of the component for sending data sequence is eliminated and from the second number from the first digital signal sequences Word signal sequence eliminates the signal of the component for sending data sequence in coupling part 46 by conjunction ripple, closes the signal after ripple and is transfused to To in signal power calculating part 47 and special frequency band component of signal removing unit 48.

Signal power calculating part 47 judges frequency component according to each frequency component for the frequency spectrum being input into from coupling part 46 Power whether be more than K times of power relative to mean power.Signal power calculating part 47 is calculated relative to mean power tool There are the meansigma methodss of the power of the frequency component of more than K times of power.Signal power calculating part 47 is average by the power for calculating Value is exported to SN as signal power than calculating part 50.

Noise power calculation portion 49 divides according to each frequency for the frequency spectrum being input into from special frequency band component of signal removing unit 48 Power to judge frequency component is measured whether relative to mean power as more than K times of power.Noise power calculation portion 49 calculates There are the meansigma methodss of the power of the frequency component of the power less than K times relative to mean power.Noise power calculation portion 49 will count The meansigma methodss of the power for calculating are exported to SN as noise power than calculating part 50.Further, noise power calculation portion 49 is not being entered According to the work(of the signal of change frequency component from the input of special frequency band component of signal removing unit 48 in the case of the above-mentioned judgement of row The meansigma methodss of rate also may be used.

SN in present embodiment, by above-mentioned structure and process, is being carried out using polarization multiplexing than computing device 4 In the case of optical transport or the situation of the frequency band of the measure of noise power cannot ensure due to high density channeling Under, it is also possible to stably calculate, determine SN ratios according to the digital signal sequences of the component comprising special frequency band signal sequence.This Outward, the special frequency band signal sequence with regard to using in the present embodiment（Training sequence signal）, it is dry with transmission data sequence Disturb and be suppressed relatively low, therefore, answered in the case where the optical transport using polarization multiplexing is carried out or due to high density frequency With, High Speed Modulation etc. make transmission data sequence occupy it is wide band in the case of, it is also possible to stably calculate SN ratios.

Additionally, in the present embodiment, illustrate to judge spy in signal power calculating part 47 and noise power calculation portion 49 The structure that will be judged as benchmark relative to the power that mean power is K times when determining the component of band signal sequence.Can It is, however it is not limited to this, predetermined threshold power also may be used as benchmark come the component for judging special frequency band signal sequence.This Outward, it is also possible to when the power of special frequency band signal sequence is calculated in signal power calculating part 47, deduct in noise power calculation The noise power calculated in portion 49.

Additionally, in the calculating of noise power, it is also possible in the frequency for concentrating the power of special frequency band signal sequence Between frequency band near frequency（For example, the frequency band of the 12.5GHz comprising 0GHz）As object.With regard to the frequency band of 12.5GHz, example Such as, the frequency band from -6.75GHz to 6.75GHz is selected.This is to ask for light SN ratios（Optical Signal to Noise Ratio：OSNR）, OSNR is often in order to representing in optical communications the state of signal and being used, its definition is the frequency of 12.5GHz The ratio of noise power and signal power in band.Further, using following formula（4）To calculate OSNR.

OSNR =（Whole signal powers）/（The noise power of 12.5GHz frequency bands） …（4）

Additionally, in the present embodiment, illustrate that signal power calculating part 47 and noise power calculation portion 49 are processing right The meansigma methodss of power are calculated in the frequency band of elephant and using the meansigma methodss for calculating as signal power and the structure of noise power.Can Be, however it is not limited to this, it is also possible to ask for per 1 sample signal power and noise power come calculate per 1 sample SN ratios.This When, it is equivalent to 12.5GHz, so as to calculate by being expanded or shunk the SN ratios sampled per 1 according to the interval between sampling OSNR also may be used.For example, the interval between sampling and 10MHz to it is corresponding when make per 1 the SN ratios of sampling for 1250 times to be scaled phase When in the value of 12.5GHz.

Additionally, in the present embodiment, illustrate that noise power calculation portion 49 is based on comprising special frequency band signal sequence Noise component(s) in interval is calculating the structure of noise power.But, in the case that the dispersion in light transmission path is larger, letter The speed advanced number in light transmission path is different according to frequency.Therefore, in digital signal sequences, comprising special frequency band Interval and comprising the calculating that be used for SN ratios the interval of noise component(s) of the component of signal sequence produces difference.For example, as above State like that, by the input of wavelength dispersion amount calculating part 1007（First digital signal sequences and the second digital signal sequences）As In the case of the output of analog/digital conversion portion 1003-1 and 1003-2, what the power based on special frequency band signal sequence was concentrated Frequency also may be used come the interval for determining the calculating for noise power.Specifically, determine to calculate noise as going out as shown in figure 21 The interval of power.

Figure 21 is the figure of the summary of the interval decision for illustrating the calculating for being used for noise power in the present embodiment.At this In figure, horizontal axis representing time, the longitudinal axis represents frequency.In the example shown in the figure, the power of special frequency band signal sequence is concentrated In frequency fa and fb.Dispersion values at frequency fa are set to into Da, the dispersion values at frequency fb are set to into Db.Due to the shadow of dispersion Ring, the interval only comprising special frequency band signal sequence is different according to frequency.The component of special frequency band signal sequence is in frequency fa The moment ta of appearance is different in the moment tb that frequency fb occurs from the component of special frequency band signal sequence.But, by using when Carve ta and tb such that it is able to the interval beginning for sending data sequence will not be included at the intermediate frequency of frequency fa and frequency fb Moment obtain for（（ta+tb）/2）.Additionally, the dispersion at intermediate frequency also can be obtained for（（Da+Db）/2）.By the moment （（ta+tb）/2）Noise work(is determined in the interval of the length identical length with special frequency band signal sequence as start time Rate, thereby, it is possible to obtain noise power in the case of not comprising the component for sending data sequence A or transmission data sequence B.This Outward, however it is not limited to intermediate frequency（（fa+fb）/2）, by using moment ta and tb and dispersion Da and Db such that it is able to obtain The noise power at frequency beyond frequency fa and fb.

Additionally, by using the information of moment ta and tb such that it is able to which the dispersion of the optical signal to receiving is compensated. By the compensation for carrying out dispersion, so as to the time difference of the optical signal of each frequency is eliminated, therefore, it is possible to need not be according to each The special frequency band signal sequence of whole frequency bands is extracted in the case of frequency partition.

In this case, training sequence signal test section 1102 according to special frequency band signal sequence power concentrate each Frequency is specified to interval, also, specify for determine calculate SN than when the frequency band of noise power that uses Interval.Additionally, memorizer 1101-1 and 1101-2 or time-domain window portion 1105-1 and 1105-2 pair and special frequency band signal sequence Individually extracted in corresponding interval and for noise the interval of each frequency of row.Thus, in the case where dispersion is larger, Precision noise power can be well obtained in the case of not comprising the component for sending data sequence, it is possible to increase the essence of SN ratios Degree.

Figure 22 is to illustrate block diagrams of the SN than another configuration example of computing device.As going out as shown in the drawing, SN is than calculating Device 4B possess coupling part 64, special frequency band component of signal removing unit 65, low frequency band component removing unit 66, IFFT operational parts 67, Signal/noise power calculation portion 68, buffer portion 69 and SN are than calculating part 70.Each portion in these each portions and Figure 17 such as with Lower correspondence like that.That is, coupling part 64 is corresponding with coupling part 1204-n, special frequency band component of signal removing unit 65 and low band signal Component removing unit 66 is corresponding with the n-th band filter of frequency domain portion 1801-1-n and 1801-2-n, IFFT operational parts 67 and IFFT Department 1802-1-n is corresponding with 1802-2-n, signal/noise power calculation portion 68 and power calculation portion 1203-1-n and 1203-2-n pair Should, SN is more corresponding with calculating part time delay 1206 than calculating part 70.Further, in Figure 17 and Figure 22, coupling part 64 and coupling part The position of 1204-n is different, but, in the case of signal calculated power or noise power, with the situation of computing relay time not Together, power is calculated, therefore, the position for configuring coupling part is the frequency domain before IFFT computings and the time domain after IFFT computings Which can, Filtering Processing and power calculation carried out after ripple is closed process more cut down circuit scale.Hereinafter, in figure Illustrate in the case of 22 structure.

What coupling part 64 pairs was input into respectively from memorizer 1101-1 and 1101-2 or time-domain window portion 1105-1 and 1105-2 The signal of frequency domain is synthesized, and the signal of the frequency domain obtained by synthesis is exported to special frequency band component of signal removing unit 65. Signal sequence is extracted in memorizer 1101-1 and 1101-2 or time-domain window portion 1105-1 and 1105-2 from training sequence signal In the case of row, in the signal of the signal of the frequency domain synthesized in coupling part 64 and the frequency domain exported from coupling part 64, do not include Send the component of data sequence and include the component of training sequence signal and noise.Additionally, in memorizer 1101-1 and 1101-2 Or from sending in the case that data sequence extracts signal sequence in time-domain window portion 1105-1 and 1105-2, in coupling part 64 In the signal of the signal of the frequency domain of synthesis and the frequency domain exported from coupling part 64, include not comprising the component of training sequence signal Send the component of data sequence and noise.Further, each frequency point can be directed at than the method for the conjunction ripple in computing device as SN The phase place of amount is being separately summed, it is also possible to calculate the power of each frequency component to be separately summed.

Special frequency band component of signal removing unit 65 removes special frequency band letter from the signal of the frequency domain being input into from coupling part 64 The frequency component of number sequence is simultaneously exported to low frequency band component removing unit 66.For exporting from special frequency band component of signal removing unit 65 Frequency domain signal, from training sequence signal in memorizer 1101-1 and 1101-2 or time-domain window portion 1105-1 and 1105-2 In the case of extracting signal sequence, become the signal comprising noise component(s).On the other hand, in memorizer 1101-1 and 1101-2 Or from sending in the case that data sequence extracts signal sequence in time-domain window portion 1105-1 and 1105-2, for from specific frequency The signal of the frequency domain of the output of band signal component removing unit 65, becomes the letter comprising the component and noise component(s) for sending data sequence Number.

Signal processing in special frequency band component of signal removing unit 65 is carried out in a frequency domain.In special frequency band signal point The component of the frequency that the frequency component removed in amount removing unit 65 is concentrated for the power of special frequency band signal sequence.Due to specific frequency The frequency that the power of band signal sequence is concentrated is known, so, the removing of special frequency band component of signal is made up of band filter Portion 65, the component of the frequency that power is concentrated is removed also may be used.Additionally, being made up of the removing of special frequency band component of signal low pass filter Portion 65, the component for extracting the low-frequency band of the component of the frequency concentrated not comprising power also may be used.

Low frequency band component removing unit 66 is removed from the signal of the frequency domain being input into from special frequency band component of signal removing unit 65 The frequency component of near DC is simultaneously exported to IFFT operational parts 67.The frequency of the component removed by low frequency band component removing unit 66 Scope is from direct current（0Hz）To the scope of predetermined assigned frequency.For example, it is stipulated that frequency is based in transmission data sequence Comprising frequency component etc. determining.

It is to remove due to entering to the manipulator in optical signal transmitter that here removes the frequency component of near DC The DC component that the bias that row drives swings in time and produces in sending signal.This is because, determining noise power When, the power of the frequency component of the near DC is calculated than actual power greatly sometimes, deteriorates precision of the SN than calculating.

Figure 23 is the figure of the frequency spectrum for illustrating the special frequency band signal sequence after the transmission for determining in an experiment.In the figure, Transverse axis represents frequency, and the longitudinal axis represents power.As going out as shown in the drawing, can observe the power of DC component with carrier wave Situation about occurring at the corresponding frequency of frequency.As the example of the manipulator for using in optical communications, there is Mach-Zehnder Type photomodulator.Figure 24 is the figure of the structure for illustrating Mach-Zehnder type photomodulators.As going out as shown in the drawing, Mach-Zehnder type photomodulators possess two amplitude modulaors and a phase-modulator, carry out single sideband modulation.

Single sideband modulation is also referred to as unilateral wave band modulation, is by the way that two amplitude modulation components of 90 ° of phase are entered The mode that row closes ripple and is modulated in the frequency band of half compared with double sideband modulation.In the figure, from two Modulation and Amplitude Modulations Device exports respectively amplitude-modulated signal.To an amplitude-modulated signal in two amplitude-modulated signals by phase-modulator with Phase place is modulated relative to the mode that another amplitude-modulated signal differs 90 °.In order to offset DC component, need suitably Bias in two amplitude modulaors of control.But, due to temperature change etc., the bias being driven to manipulator swings, because This, it is difficult to ideally remove DC component.Further, because the laser of sending side and receiving side has line width, so, its frequency It is not direct current and is frequency band corresponding with line width.

As the method for the low frequency component for removing near DC, there is the side using band elimination filter or band filter Method.In the case of using band elimination filter, by the signal with the frequency domain for being input in low frequency band component removing unit 66 The wave filter for suppressing the frequency characteristic of the low frequency component of near DC is applied to low frequency band component removing unit 66.Filtered using band logical In the case of ripple device, the signal that application has the frequency domain for being input in low frequency band component removing unit 66 does not include special frequency band The wave filter of the frequency characteristic of the component of the component of signal sequence and the low frequency of near DC.In the situation using band filter Under, special frequency band component of signal removing unit 65 and low frequency band component removing unit 66 can be constituted with a circuit.Low frequency band component Removing unit 66 carries out in a frequency domain signal processing in the same manner as special frequency band component of signal removing unit 65.Further, in described above In, with special frequency band component of signal removing unit 65 and low frequency band component removing unit 66, each respectively the structure with filter circuit is entered Explanation is gone, but it is also possible to above-mentioned 2 removing units are made 1 to be filtered process.Additionally, special frequency band signal point Amount removing unit 65 and low frequency band component removing unit 66 can also be based respectively on the frequency shift (FS) from frequency offset computations portion 1103 Value of calculation carry out correcting frequency shift.

Figure 22 is returned to, proceeds the explanation of structures of the SN than computing device 4B.

IFFT operational parts 67 carry out IFFT and convert by the signal of the frequency domain to being input into from low frequency band component removing unit 66 For the signal of time domain.IFFT operational parts 67 are defeated to signal/noise power calculation portion 68 by the signal of the time domain obtained by IFFT Go out.In IFFT in IFFT operational parts 67, using as the frequency separation of the object of IFFT with a part with last time IFFT The mode that the middle frequency separation as object repeats cuts out from frequency spectrum.

The power of the signal of the time domain that signal/68 pairs, noise power calculation portion is input into from IFFT operational parts 67 is calculated. Signal/noise power calculation portion 68 is based on training sequence signal in the signal of the time domain being input into（Special frequency band signal sequence） Signal in the case of, using the power for calculating as noise power store in buffer portion 69.Additionally, signal/noise work( In the case that rate calculating part 68 is based on the signal for sending data sequence in the signal of the time domain being input into, by the power for calculating Store in buffer portion 69 as signal power.

The signal power and noise power calculated by signal/noise power calculation portion 68 is stored in buffer portion 69.

When carrying out stipulated number in signal/noise power calculation portion 68（M, M are more than 1 integer）Power calculating When, when calculating M signal power and during noise power, SN is based on the signal work(being stored in buffer portion 69 than calculating part 70 Rate and noise power are calculating SN ratios.SN than calculating part 70 calculate SN than when read in buffer portion 69 store signal work( Rate comes the meansigma methodss of signal calculated power, also, the noise power of reading storage in buffer portion 69 to calculate noise power Meansigma methodss.Further, since the power comprising noise component(s) in the signal power stored in buffer portion 69, so, SN ratios Calculating part 70 deducts the meansigma methodss of noise power from the meansigma methodss of signal power, according to subtraction result and noise power Meansigma methodss are calculating SN ratios.Further, noise power meansigma methodss relative to signal power meansigma methodss it is little in the case of, also may be used To calculate SN ratios in the case where above-mentioned subtraction is not carried out.

In SN is than computing device 4B, in calculated power value, switch in data sequence and training sequence signal is sent Its object, thus, it is also possible to be used according to the circuit for sending data sequence signal calculated power and for according to training signal Sequence calculates the circuit of noise power and changes jointly, can seek the reduction of circuit scale.Additionally, SN possesses low than computing device 4B Band component removing unit 66, therefore, it is possible to remove dividing for the near DC being included in optical signal transmitter in optical signal Amount, further, it is possible to make the measurement accuracy of noise power stable and improve the precision of SN ratios.

Additionally, in SN than in computing device 4B, using the setting IFFT operational parts before signal/noise power calculation portion 68 67 structure, makes the calculation process in light signal receiving more identical than the order of the calculation process in computing device 4B with SN. That is, adopt carries out the structure of signal processing according to the order of Filtering Processing, IFFT process, power calculation.Thereby, it is possible to seek light Signal receiving device and SN than computing device 4B in each circuit sharing, light signal receiving and SN can be sought than meter Calculate the reduction of the circuit scale of device 4B.

Additionally, in the SN of present embodiment is than computing device 4B, entering to signal power and noise power exemplified with possessing Signal/noise power calculation portion 68 that row is calculated and according to signal power and noise power calculation send the power of data sequence with Structures of the SN of the power ratio of noise than calculating part 70.But, possess any one and other also may be used using different structures.

By using each SN above than computing device, so as in optical communications regardless of the transmission using polarization multiplexing, biography How is structure in defeated path, can access signal to noise power ratio.

Further, in SN is than computing device 4, with SN than in the same manner as computing device 4B, arranging the component for removing near DC Low frequency band component removing unit 66 also may be used.Thereby, it is possible to remove the direct current being included in optical signal transmitter in optical signal Neighbouring component, further, it is possible to make the measurement accuracy of noise power stable and improve the precision of SN ratios.

In addition it is also possible to generate training sequence signal generating unit 104-l believe in the special frequency band as following explanation Number sequence.For example, it is also possible to generate the envelope shape of the frequency spectrum for sending data sequence and the frequency spectrum of special frequency band signal sequence For the special frequency band signal sequence of proportionate relationship.Figure 25 is to illustrate the frequency spectrum and special frequency band signal sequence that send data sequence Frequency spectrum is the figure of the example of the special frequency band signal sequence of proportionate relationship.In the figure, transverse axis represents frequency, and the longitudinal axis represents work( Rate.In the figure, show that power concentrates on the special frequency band signal sequence of 8 frequencies（N=8）Frequency spectrum.By using so Special frequency band signal sequence, so as to the deterioration of the SN ratios such as characteristic of wave filter used according to coherent communication system etc. Degree according to the different situation of each frequency under, it is also possible to the SN ratios to reflecting the impact of different deteriorations at each frequency Calculated.Furthermore it is possible to improve the precision of calculated SN ratios.Further, the specific frequency with frequency spectrum as shown in Figure 25 Band signal sequence can be obtained by adjusting the amplitude of alternating signal.Additionally, sending the envelope of the frequency spectrum of data sequence Can be obtained by simulation.

In addition it is also possible to generate the density at the interval of the frequency of the power concentration of special frequency band signal sequence and send data The power level of sequence is the special frequency band signal sequence of proportionate relationship.Figure 26 is the power collection for illustrating special frequency band signal sequence In density and the power level for sending data sequence at interval of frequency there is the special frequency band signal sequence of proportionate relationship The figure of one example of frequency spectrum.In the figure, transverse axis represents frequency, and the longitudinal axis represents power.In the figure, show that power is concentrated In the special frequency band signal sequence of 6 frequencies（N=6）Frequency spectrum.In such special frequency band signal sequence, based on transmission number According to sequence signal frequency spectrum changing the interval of alternating signal, the interval thereby, it is possible to adjust the frequency of power concentration is dredged It is close.

Sometimes due to the wave filter used in the transmission of optical signal makes the frequency spectrum of special frequency band signal sequence and sends number According to the frequency spectrum stricturization together of sequence.In this case, special frequency band after using by stricturization and power level changes When signal sequence carrys out power estimator signal, precision is reduced.For example, it is assumed that using have centered on carrier wave and power is concentrated on In the case of the special frequency band signal sequence of the frequency spectrum of unilateral each 2 frequency, due to the impact of wave filter, the 2 of high frequency side The each 3dB of power drop at individual frequency.When the power of 1 special frequency band signal sequence is set to into 1, in the shadow without wave filter When ringing, total 4 power is obtained, but, total 3 power is had to when there is the impact of wave filter.Then, it is estimated Compared with signal power is when the impact without wave filter, power is changed into 3/4.Due to the impact of wave filter, data sequence is sent Power also declines, but, send the power of data sequence due to concentrating on central part, so, will not drop to 3/4 situation compared with It is many.In this case, by using the special frequency band signal sequence as shown in Figure 26 such that it is able to suppress power The impact of frequency dependence, it is possible to increase the precision of the SN ratios for being calculated.

In addition it is also possible to the power level generated at each frequency of the power concentration of special frequency band signal sequence is logical with relevant The proportion of goods damageds of the frequency characteristic in letter system are the special frequency band signal sequence of inversely prroportional relationship.Figure 27 is to illustrate that special frequency band is believed The proportion of goods damageds of the frequency characteristic in the power level at each frequency that the power of number sequence is concentrated and coherent communication system are inverse ratio The figure of one example of the frequency spectrum of the special frequency band signal sequence of example relation.In the figure, transverse axis represents frequency, and the longitudinal axis represents work( Rate.In the figure, show that power concentrates on the special frequency band signal sequence of 4 frequencies（N=4）Frequency spectrum.

For example there is the frequency characteristic same with optical signal transmitter, light transmission path and light signal receiving In the computer simulation of system, can be according to the FIR used in light signal receiving（Finite Impulse Response, finite impulse response）Tap coefficient of wave filter etc. is asking for the frequency characteristic of coherent communication system.Or, In coherent communication system, the frequency point in the whole frequency bands utilized in the transmission for sending data sequence with same level is transmitted The signal sequence of amount, analyzes each frequency component in light signal receiving, thus, asks for the frequency characteristic of coherent communication system Also may be used.By using the special frequency band signal sequence as shown in Figure 27 such that it is able to make the work(of special frequency band signal sequence Rate concentrate each frequency at power it is equal, suppress in power estimator signal by frequency characteristic affected, it is possible to increase The precision of the SN ratios for being calculated.

Additionally, the structure as SN than computing device 4B, illustrates that signal/noise power calculation portion 68 is based on IFFT computings The signal of the time domain that portion 67 is converted carrys out the structure of signal calculated power and noise power.But, however it is not limited to the structure, letter Number/noise power calculation portion 68 can also in the case where the signal of the time domain converted in IFFT operational parts 67 is not used root The signal of the frequency domain exported according to low frequency band component removing unit 66 carrys out any one of signal calculated power and noise power or both.

（Second embodiment）

Then, second embodiment of the present invention is illustrated.Here, pair saying with the difference of first embodiment It is bright.

Figure 28 is the block diagram of the configuration example for illustrating the optical signal transmitter in second embodiment.In present embodiment Optical signal transmitter possesses sending signal modulation portion 101 and 201, signal multiplexing portion 102 and 202, the and of electrical/optical transformation component 103 203rd, 2 × L training sequence signal generating unit 104-1 ~ 104-L, 204-1 ~ 204-L, the and of training sequence signal selector 105 205 and polarization multiplexing portion 206.In the figure, with first embodiment in optical signal transmitter（Fig. 1）Difference It is that sending signal modulation portion 201, signal multiplexing portion 202, electrical/optical transformation component 203, training have been added for polarization multiplexing Signal sequence generating unit 204-l（1≤l≤L, L >=2）, training sequence signal selector 205 and polarization multiplexing portion 206.

Sending signal modulation portion 201, signal multiplexing portion 202, electrical/optical transformation component 203, training sequence signal generating unit 204- l（1≤l≤L, L >=2）, training sequence signal selector 205 carries out respectively and sending signal modulation portion 101, signal multiplexing portion 102nd, electrical/optical transformation component 103, training sequence signal generating unit 104-l（1≤l≤L, L >=2）, training sequence signal selector 105 same work, light sending signal is generated using the data signal sequence of polarization multiplexing.However, it is also possible in polarized wave Between have training sequence signal generating unit 104-l（1≤l≤L, L >=2）And 204-l（1≤l≤L, L >=2）, training sequence signal Selector 105 and 205.

Additionally, training sequence signal generating unit 104-1（1≤l≤L, L >=2）And 204-l（1≤l≤L, L >=2）, training Signal sequence selector 105 and 205 is in the different signals between polarized wave of part or all of generation of its sequence and carries out sending out Also can send, the same signal of generation is multiplexed also may be used.In the case where being multiplexed to same training sequence signal, it is also possible to generation For possessing training sequence signal generating unit 104-l（1≤l≤L, L >=2）And 204-l（1≤l≤L, L >=2）, training sequence signal Selector 105 and 205 and by 1 training sequence signal generating unit communization.By carrying out communization, so as to send out in optical signal In sending device, same special frequency band signal is sent with two orthogonal polarized waves, in light signal receiving, to not carrying out pole Changing detached signal can also calculate wavelength dispersion amount.

As an example, figure 29 illustrates same special frequency band signal time-multiplexed to data signal to be transmitted When frame format.Figure 29 is frame format when illustrating special frequency band signal time-multiplexed to data signal in the present embodiment The skeleton diagram of one example.As shown in the drawing, to 2 sequences respectively according to each transmission data signal Ns symbol insertion alternation letter Number Nt symbols.Training signal of the alternating signal equivalent to first embodiment, it is also possible to using whole identical sequences, it is also possible to It is different according to each sequence.Additionally, also may be used according to the different plane of polarization sending signal of each sequence.By in different pole Change face sends training signal, even if in the case of so as to there occurs polarized rotation in a transmission path, it is also possible to receiving side joint Receive at least any one signal.

The signal that two polarized waves of use generated by electrical/optical transformation component 103 and electrical/optical transformation component 203 send is by polarization Multiplexing unit 206 carries out polarization multiplexing, and the signal after multiplexing is transmitted as sending signal.

Figure 30 is the block diagram of the configuration example for illustrating the light signal receiving in present embodiment.Light in present embodiment Signal receiving device possesses polarization division portion 1001, optical electrical transformation component 1002-1 and 1002-2, analog/digital conversion portion 1003- 1 and 1003-2, wavelength dispersion compensation portion 1004-1 and 1004-2, adaptive equalization portion 2005, demodulation section 1006 and 2006 and Wavelength dispersion amount calculating part 1007.In the figure, with first embodiment in light signal receiving（Fig. 7）Difference exists In, demodulation section 2006 is also equipped with, also, replace adaptive equalization portion 1005 and possess adaptive equalization portion 2005.

Adaptive equalization portion 2005 by the Signal separator after polarization multiplexing, by the signal sequence of each polarized wave respectively to solution Tune portion 1006,2006 exports.Additionally, 2 demodulation sections 1006 and demodulation section 2006 pairs are input into respectively from adaptive equalization portion 2005 The signal sequence of polarized wave be demodulated.

Further, in the same manner as first embodiment, as training sequence signal, before and after special frequency band signal sequence, Insertion power concentrates merely on the second special frequency band signal sequence of the characteristic frequency different from special frequency band signal sequence, thus, The interference caused by the sending signal sequence before and after training signal of the frequency band used to special frequency band signal sequence is prevented, Therefore, as illustrated in FIG. 14 as the peak value of performance number clearly occur, power can be correctly detected for maximum when Sampling instant T₁With sampling instant T₂。

Additionally, with first frequency band filter portion 1202-1-1 and first frequency band filter portion 1202-2-1, And removing second is specific in second frequency band filter portion 1202-1-2 and second frequency band filter portion 1202-2-2 The mode setpoint frequency band filter of band signal sequence, thereby, it is possible in computing relay time difference, remove special frequency band The signal of the second special frequency band signal sequence slightly before and after a while of signal sequence, only extracts the first special frequency band signal sequence Row, therefore, the estimated accuracy of wavelength dispersion is improved.

Hereinafter, the effect of embodiments of the present invention is illustrated.

Figure 31 and Figure 32 are to be shown respectively for the special frequency band signal sequence shown in Fig. 3 and Fig. 4 to be used as training sequence signal Computer simulation results chart.Baud rate will be sent and be set to 31.8Gbaud, OSNR is set to into 12dB.With regard to transmission path, It is assumed that single-mode fiber（SMF）, the wavelength dispersion of additional 40,000ps/nm and the polarization mould of 32ps are shown in Figure 31 and Figure 32 Dispersion（PMD）Result afterwards.Additionally, in transmission frame format, special frequency band signal sequence is set to into 160 symbols.

Wavelength dispersion value when first special frequency band signal to be used as training sequence signal according to result, shown in Figure 31 Result of calculation and Figure 32 shown in wavelength dispersion value when second special frequency band signal to be used as training sequence signal meter Calculate result to compare, estimated accuracy is more superior.This is because, with regard to the bandwidth of the peak value of 2 frequency spectrums of special frequency band signal, first It is individual bigger, therefore, delay-time difference also becomes big, and with this concomitantly, resolution also becomes big, so, estimation difference diminishes.But, Nyquist filter is used as into band limiting filter in sending side（Transmitting filter）In the case of, when using first specific frequency During band signal, as illustrated in FIG. 5 as, due to the impact of wave filter, the signal power of special frequency band signal diminishes, it is impossible to enough Estimated.

On the other hand, in the case of using second special frequency band signal, as illustrated in FIG. 6 as do not send filter The impact of ripple device, therefore, become the characteristic equal with the result shown in Figure 32.Therefore, in the case of without transmitting filter, Using first high special frequency band signal sequence of estimated accuracy, in the case where there is transmitting filter, using in the situation Under second special frequency band signal sequence also being estimated, thereby, it is possible to realize that wavelength dispersion is estimated in receiving side.This When, due to estimated accuracy sacrifice, so, in order to improve estimated accuracy, increase and estimate number of times or increase in the average of estimated value The quantity of the estimated value used in change is improving estimated accuracy.

Additionally, concentrating on the frequency bands different from first frequency band by generating first special frequency band signal sequence and power Second special frequency band signal sequence, select any one by training sequence signal selector to carry out time-multiplexed and send, So as to also according to the stricturization of the signal in the repeater in transmission path（PBN：Path Band Narrowing）, transceiver Power amplifier, digital-to-analog converter（DAC）, analog-to-digital converter（ADC）, analog band-pass filter（BPF： Band Pass Filter）Deng front end（FE）The impact of the frequency characteristic in portion etc. is adaptively switching special frequency band signal sequence Row, thereby, it is possible to carry out acceptance division in wavelength dispersion estimation.

As described above, in embodiments of the present invention optical signal transmitter and optical signal transmitter has been used Coherent communication system in, when the mid frequency of training signal in receiving signal deviate from, can also realize wavelength dispersion amount Estimation, by the estimated wavelength dispersion amount of compensation such that it is able to improve the decoding precision for receiving signal.Additionally, due to Each device, the wave filter of propagation path or frequency shift (FS), phase offset etc. receive the mid frequency of the training signal in signal When deviate from, signal is being received by ROADM（Reconfigurable Optical Add/Drop Multiplexer, restructural Optical add/drop multiplexer）Or the use of the frequency received included in signal is narrow-band during the stricturization such as nyquist filter Training signal, is robustly estimated for stricturization, receive signal not by stricturization when, using it is wide band training believe Number, it is possible to increase estimated accuracy.

Additionally, in optical signal transmitter, training sequence signal generating unit 104-1 ~ 104-L generates multiple alternating signals As training sequence signal, frequency characteristic of the training sequence signal selector 105 in coherent communication system come select and send out Signal sequence is sent to carry out time-multiplexed training sequence signal.In light signal receiving, training sequence signal test section Training sequence signal included in 1102 pairs of signals for receiving detects that frequency offset computations portion 1103 calculates and receives letter Frequency shift (FS) in number, the computing relay amount after it compensate for frequency shift (FS) of retardation calculating part 1104.Like this, in the present invention Embodiment optical signal transmitter and used the coherent communication system of optical signal transmitter, can suppress to propagate The impact of the frequency characteristic in path etc., estimates wavelength dispersion amount.

For example, in the case of the impact without wave filter completely, as shown by Figure 31 and Figure 32, instruct with using The situation for practicing signal for the alternating signal of " 1100 " of narrow-band is compared, using the alternation that training signal is wide band " 1010 " Estimation difference can be more suppressed to 1/2 or so by signal.On the other hand, in the case of using nyquist filter, with regard to The alternating signal of " 1010 ", as illustrated in FIG. 5 as, S/N deterioration 6dB or so, the deterioration in accuracy of estimation.On the other hand, close In the alternating signal of " 1100 ", can be estimated in the case where not being affected.

When using specific example to be further illustrated, in the absolute value for deviateing frequency shift (FS), phase offset Maximum be set to 5GHz, set baud rate Rs=31.8Gbaud and by the nyquist filter for using in a transceiver i.e. The frequency band of BPF is set to ± Rs/2（=15.9GHz）In the case of, when the special frequency band signal that ± 15.9GHz is concentrated on using power During sequence, a part of frequency spectrum is present in identical with the cut-off frequency of wave filter or bigger than its frequency, loses special frequency band signal The power of at least one frequency spectrum of sequence.On the other hand, when the special frequency band signal sequence that ± 7.95GHz is concentrated on using power During row, even if in the case where there is frequency shift (FS), power also focuses on maximum ± 12.95GHz, therefore, these frequencies are ratio The little frequency of the cut-off frequency of wave filter, can calculate wavelength dispersion amount.For example, under conditions of shown in Figure 12, can be with 10^-2 Probability realize estimation difference ± 250ps/nm.

More than, with reference to the accompanying drawings of embodiments of the present invention, however, it should be apparent that above-mentioned embodiment is only originally The illustration of invention, the present invention is not limited to above-mentioned embodiment.Accordingly it is also possible to without departing from the present invention technological thought and The additional of structural element, omission, replacement, other changes are carried out in the range of scope.

Industrial applicability

According to the present invention, by the special frequency band signal used in optical signal transmitter and light signal receiving, from And wavelength dispersion amount can be carried out in the case where not affected by transmission path, the wave filter of transceiver, frequency characteristic Estimate, can compensate for the distortion of sending signal caused by wavelength dispersion.

The explanation of reference

4th, 4B SN compare computing device

46 coupling part

47 signal power calculating parts

48 special frequency band component of signal removing units

49 noise power calculation portions

50 SN compare calculating part

64 coupling part

65 special frequency band component of signal removing units

66 low frequency band component removing units

67 IFFT operational parts

68 signals/noise power calculation portion

69 buffer portions

70 SN compare calculating part

101st, 201 sending signal modulation portion

102nd, 202 signal multiplexing portion

103rd, 203 electrical/optical transformation component

104-1,104-2,104-L, 104-l, 204-1,204-L, 204-l training sequence signal generating unit

105th, 205 training sequence signal selector

206 polarization multiplexing portions

1001 polarization division portions

1002-1,1002-2,1002-i optical electrical transformation component

1003-1,1003-2,1003-i analog/digital conversion portion

1004-1,1004-2,1004-i wavelength dispersion compensation portion

1005th, 2005 adaptive equalization portion

1006th, 2006 demodulation section

1007 wavelength dispersion amount calculating parts

1101-1,1101-2,1101-i memorizer

1102 training sequence signal test sections

1103 frequency offset computations portions

1104 retardation calculating parts

1105-1,1105-2 time-domain window portion

1201-1,1201-2 signal dispenser

1202-1-1、1202-1-2、1202-1-N、1202-2-1、1202-2-2、1202-2-N、1202-1-h、1202- 1-k, 1202-1-n, 1202-2-n frequency bandpass filter portion

1203-1-1、1203-1-2、1203-1-N、1203-2-1、1203-2-2、1203-2-N、1203-1-n、1203- 2-n power calculation portion

1204-1,1204-2,1204-N, 1204-h, 1204-k, 1204-n coupling part

1205-1,1205-2,1205-N, 1205-n averaging filter portion

1206 time delay calculating part

1501-1,1501-2 FFT portions

1801-1-1,1801-1-N, 1801-1-n, 1801-2-1,1801-2-N, 1801-2-n frequency domain the n-th frequency band logical Wave filter portion

1802-1-1,1802-1-N, 1802-1-n, 1802-2-1,1802-2-N, 1802-2-n IFFT Department

2101-1-1、2101-1-2、2101-1-L、2101-2-1、2101-2-2、2101-2-L、2101-1-l、2101- 2-l band filters portion

2102-1,2102-2,2102-L, 2102-l signal power calculating part

2103 training signal switching parts

2104 timing detection units

3101-1-1,3101-1-L, 3101-2-1,3101-2-L, 3101-1-l, 3101-2-l band filter portion

3102-1,3102-L, 3102-l training signal power calculation portion

3103 training signal switching parts

3104 side-play amount calculating parts

3501-1-1,3501-1-L, 3501-1-l, 3501-2-1,3501-2-L, 3501-2-l frequency domain band filter Portion

3502-1-1,3502-1-L, 3502-1-l, 3502-2-1,3502-2-L, 3502-2-l IFFT Department.

Claims

1. a kind of coherent communication system, possesses optical signal transmitter and light signal receiving, wherein,

The optical signal transmitter possesses：

Training sequence signal generating unit, generates multiple signal sequences, the i.e. power with the power for concentrating on multiple frequency bands and concentrates In each different frequency band multiple signal sequences as multiple training sequence signals；

Training sequence signal selector, in the plurality of training sequence signal generated from the training sequence signal generating unit Select at least one training sequence signal；

Signal multiplexing portion, generates the selected training sequence signal of the training sequence signal selector and transmission data Sequence carry out it is time-multiplexed after signal sequence；And

Electrical/optical transformation component, the signal sequence that the signal multiplexing portion is generated is changed into optical signal to be transmitted,

The light signal receiving possesses：

The converting optical signals sent from the optical signal transmitter are the signal of telecommunication by optical electrical transformation component；

Analog/digital conversion portion, is digital signal sequences by the converting electrical signal after being converted by the optical electrical transformation component；

Multiple frequency bandpass filter portions, it is corresponding respectively with the plurality of signal sequence, become the analog/digital conversion portion A part for the band component of the digital signal sequences for changing passes through；And

Multiple power calculation portions, are arranged in correspondence with respectively with the plurality of frequency bandpass filter portion, calculate corresponding frequency band The performance number of the digital signal sequences of bandpass filter portion output,

The training sequence signal generating unit generates power and concentrates on than the optical signal transmitter or optical signal reception At least one signal sequence of the little frequency of the cut-off frequency in band limiting filter in device or propagation path is used as the instruction Practice signal sequence,

The training sequence signal selector is based on the optical signal transmitter or the light signal receiving or described The presence or absence of described band limiting filter in propagation path, from the plurality of training that the training sequence signal generating unit is generated At least one training sequence signal is selected in signal sequence.

2. a kind of coherent communication system, possesses optical signal transmitter and light signal receiving, wherein,

The optical signal transmitter possesses：

The light signal receiving possesses：

Frequency of the training sequence signal selector based on the optical signal transmitter or the light signal receiving is special Stricturization, the frequency characteristic of the transmission channel of the propagation path, wavelength dispersion amount, transmission range in property, propagation path, with And at least one among the estimated accuracy of the wavelength dispersion amount, generated from the training sequence signal generating unit described in At least one training sequence signal is selected in multiple training sequence signals.

3. the coherent communication system according to claim 1 or claim 2, wherein,

The training sequence signal generating unit generates the interval of the frequency that power is concentrated and is spaced big signal sequence than predetermined Row are used as the training sequence signal.

4. the coherent communication system according to claim 1 or claim 2, wherein,

The training sequence signal selector selects multiple training sequence signals,

The signal multiplexing portion generates signal according to selected each training sequence signal of the training sequence signal selector Sequence,

The electrical/optical transformation component sends multiple signal sequences that the signal multiplexing portion is generated in different planes of polarization.

5. the coherent communication system according to claim 1 or claim 2, wherein,

Answer in the surrounding time for carrying out time-multiplexed training sequence signal with the transmission data sequence in the signal multiplexing portion Use other training sequence signals.

6. a kind of coherent communication system, possesses optical signal transmitter and light signal receiving, wherein,

The optical signal transmitter possesses：

The light signal receiving possesses：

Multiple frequency bandpass filter portions, it is corresponding respectively with the plurality of signal sequence, become the analog/digital conversion portion A part for the band component of the digital signal sequences for changing passes through；

Training signal switching part, the maximum performance number in the performance number that the selection power calculation portion is calculated；And

Training sequence signal test section, based on the selected maximum performance number of the training signal switching part, from described Digital signal sequences detection power concentrates on the power calculation portion corresponding frequency band logical filter of the performance number maximum with this is calculated The training sequence signal of the frequency band that ripple device portion is passed through.

7. coherent communication system according to claim 6, wherein,

The light signal receiving has in advance the information of selected training sequence signal with the optical signal transmitter,

The training signal switching part only selected using described information and export from the selected training sequence signal The input in corresponding frequency bandpass filter portion.

8. coherent communication system according to claim 6, wherein,

The position of the training sequence signal that the light signal receiving is detected based on the training sequence signal test section Confidence ceases, and the area comprising the training sequence signal detected described in a part is selected and extracted from the digital signal sequences Between, the interval comprising the training sequence signal detected described in all and not comprising the training sequence signal for detecting Any one interval.

9. coherent communication system according to claim 8, wherein,

The light signal receiving is also equipped with side-play amount calculating part, and the side-play amount calculating part is comprising a part of training The training sequence signal that signal sequence test section is detected described interval or comprising all training sequence signals Cut based on the training signal in digital signal sequences in the interval of the training sequence signal that test section is detected Change portion to calculate frequency shift (FS),

The frequency bandpass filter portion is in the frequency shift (FS) calculated based on the side-play amount calculating part to the digital signal Sequence is compensated after the frequency shift (FS), makes the training signal sequence in the frequency component included in the digital signal sequences The band component that the power of row is concentrated passes through,

The light signal receiving is also equipped with：

Multiple power calculation portions, are arranged in correspondence with respectively with the plurality of frequency bandpass filter portion, calculate corresponding frequency band The performance number of the digital signal sequences of bandpass filter portion output；And

Transmission path information calculating part, the performance number calculated based on the plurality of power calculation portion is calculating wavelength dispersion Amount.

10. coherent communication system according to claim 8, wherein,

The plurality of frequency bandpass filter portion is in the frequency shift (FS) calculated based on the side-play amount calculating part to described Digital signal sequences are compensated after the frequency shift (FS), make in the frequency component included in the digital signal sequences except described Band component beyond the band component that the power of training sequence signal is concentrated passes through,

The light signal receiving is also equipped with transmission path information calculating part, and the transmission path information calculating part is based on described The performance number that multiple power calculation portions are calculated is calculating noise power.

11. coherent communication systems according to claim 8, wherein,

The light signal receiving is also equipped with transmission path information calculating part, and the transmission path information calculating part is not including Digital signal sequences in the interval of the training sequence signal that the training sequence signal test section is detected are fallen into a trap Calculate signal power.

12. coherent communication systems according to claim 8, wherein,

At least one of the frequency bandpass filter portion and the power calculation portion is with than the training sequence signal test section The slow work clock of work clock be operated.

13. coherent communication systems according to claim 8, wherein,

Share in the plurality of frequency bandpass filter portion when being about to the digital signal sequences and being transformed to the signal of frequency domain FFT computings operational part or enter to be about to IFFT computings when the digital signal sequences of frequency domain are inversely transformed into the signal of time domain Operational part.

A kind of 14. communication means, the communication means is possess optical signal transmitter and light signal receiving relevant logical Communication means in letter system, wherein, have：

Training sequence signal generation step, generates multiple signal sequences, the i.e. power collection with the power for concentrating on multiple frequency bands In in each different frequency band multiple signal sequences as multiple training sequence signals；

Training sequence signal selects step, believes from the plurality of training generated in the training sequence signal generation step At least one training sequence signal is selected in number sequence；

Signal multiplexing step, generate by the training sequence signal select step selected in the training sequence signal with Send data sequence carry out it is time-multiplexed after signal sequence；

Electrical/optical shift step, the signal sequence generated in the signal multiplexing step is changed into optical signal to carry out Send；

The converting optical signals sent in the electrical/optical shift step are the signal of telecommunication by optical electrical shift step；

Analog/digital conversion step, is digital signal by the converting electrical signal after converting in the optical electrical shift step Sequence；

Frequency band pass filtering step, makes in the analog/digital conversion step according to the plurality of signal sequence each A part for the band component of the digital signal sequences after conversion passes through；And

Power calculation step, calculates the performance number of each digital signal sequences obtained in the frequency band pass filtering step,

In the training sequence signal generation step, generate power and concentrate on and believe than the optical signal transmitter or the light At least one signal sequence conduct of the little frequency of the cut-off frequency in band limiting filter in number reception device or propagation path The training sequence signal,

In the training sequence signal selects step, based on the optical signal transmitter or the light signal receiving or The presence or absence of described band limiting filter in propagation path described in person, from generated in the training sequence signal generation step At least one training sequence signal is selected in the plurality of training sequence signal.

A kind of 15. communication means, the communication means is possess optical signal transmitter and light signal receiving relevant logical Communication means in letter system, wherein, have：

In the training sequence signal selects step, based on the optical signal transmitter or the light signal receiving Stricturization, the frequency characteristic of the transmission channel of the propagation path, wavelength dispersion amount, transmission in frequency characteristic, propagation path At least one among the estimated accuracy of distance and the wavelength dispersion amount, from the training sequence signal generation step At least one training sequence signal is selected in the plurality of training sequence signal for generating.

A kind of 16. communication means, the communication means is possess optical signal transmitter and light signal receiving relevant logical Communication means in letter system, wherein, have：

Frequency band pass filtering step, makes in the analog/digital conversion step according to the plurality of signal sequence each A part for the band component of the digital signal sequences after conversion passes through；

Training signal switch step, selects the maximum performance number in the performance number calculated in the power calculation step；With And

Training sequence signal detecting step, based on the maximum performance number selected in the training signal switch step, Concentrate on included in the corresponding digital signal sequences of the performance number maximum with this from digital signal sequences detection power The training sequence signal of the frequency band of signal, the frequency band for passing through in the frequency band pass filtering step.

A kind of 17. sending methods, described sender method is possess optical signal transmitter and light signal receiving relevant logical Sending method in letter system, wherein, have：

Signal multiplexing step, generate by the training sequence signal select step selected in the training sequence signal with Send data sequence carry out it is time-multiplexed after signal sequence；And

Electrical/optical shift step, the signal sequence generated in the signal multiplexing step is changed into optical signal to carry out Send, in the training sequence signal generation step, generate power and concentrate on than the optical signal transmitter or the light At least one signal sequence of the little frequency of the cut-off frequency in band limiting filter in signal receiving device or propagation path is made For the training sequence signal,

A kind of 18. sending methods, described sender method is possess optical signal transmitter and light signal receiving relevant logical Sending method in letter system, wherein, have：

Electrical/optical shift step, the signal sequence generated in the signal multiplexing step is changed into optical signal to carry out Send,